Low-frequency Magnetic Susceptibility Research Articles

Outburst floods and their impact on Chinese Neolithic cultures during the 4.2 ka BP event: Evidence from Dayeze Lake in the lower reaches of the Yellow River

Abrupt climate fluctuations between 4.2 and 3.5 ka BP, and in particular the 4.2 ka BP event, exerted a profound impact on the global ancient civilizations. However, hydroclimatic conditions within the Asian Summer Monsoon (ASM) regions during this event remain uncertain. Here we report a multi-proxy analysis of a sediment core obtained from Dayeze Lake in the lower reaches of the Yellow River in monsoonal China, to elucidate the hydroclimatic variabilities over the past 4.2 ka. Core intervals (4.2–3.5, 1.1–0.6 cal ka BP) containing high levels of sand fraction, low-frequency magnetic susceptibility and zirconium, and low levels of organic matter and calcium oxide, reflect outburst floods from the Yellow River. This is supported by the widespread fluvial deposits and slackwater deposits preserved in archaeological sites and loess-paleosol profiles from the middle and lower reaches of the Yellow River. In contrast, various climate records, such as lake level, pollen, and tree ring data, from the marginal regions of the ASM reflect widespread droughts during the same time period. This finding highlights the significant spatial heterogeneity of hydroclimate within ASM regions associated with the 4.2 ka BP event, which may be related to migrations of the monsoonal rain belt and the West Pacific subtropical high, as well as frequent El Niño–Southern Oscillation events. Referring to archaeological data, we conclude that the decline and collapse of Chinese Neolithic cultures were related to a pattern of droughts in the marginal regions of the ASM and floods in the middle and lower reaches of the Yellow River.

Changes in the magnetic properties of a tropical red soil following the conversion of forest into agricultural land

Land uses have a large impact on the magnetic properties of soil. Understanding the changes in such properties caused by different land uses will help to correctly explain and apply magnetic parameters. In this study, the magnetic susceptibility, magnetic mineral types, and magnetic domain state of iron oxide particles in soil after the transformation of a forest into a tea garden and cornfield in a tropical area were compared. 1)The vertical distribution characteristics of soil magnetism under the three land uses in tropical red soil area were similar. The magnetic properties of soil in the 0–20 cm surface layer was significantly different, but there were no significant differences below 20 cm. The low-frequency mass magnetic susceptibility and anhysteretic susceptibility of topsoil were largest in the cornfield, followed by the forest and tea garden, and the magnetic susceptibility of the topsoil in the cornfield was significantly higher than in the tea garden and forest. 2)The magnetic minerals in tropical red soil area were mainly ferrimagnetic minerals (maghemite and magnetite). The content of ferrimagnetic minerals decreased with depth, while the content of antiferromagnetic minerals (hematite) increased. 3)The magnetic particles were mainly composed of superparamagnetic (SP), single domain (SD), and pseudo single domain (PSD) particles. The magnetic differences in the topsoil were mainly caused by changes in the ferrimagnetic mineral concentration of SD particles. Tea garden and cornfield are the two main agricultural land in the study area. Through the correct application of magnetic parameters, it is helpful to monitor the influence of land use change on soil properties, so as to provide the necessary reference for the rational use of soil.

Topsoil's magnetic and electrical properties in a volcanic and tropical region.

Environmental monitoring by measuring topsoil's magnetic and electrical properties is one practical, quick, and low-cost approach. This method has been used worldwide as a proxy for the presence of potentially toxic elements. However, additional research must be conducted on diverse soil types, geology, and climates. We determined the magnetic and electrical properties of urban and agricultural topsoils in a volcanic region and analyzed them as possible proxies of potentially toxic elements for environmental monitoring. To identify topsoil characteristics, we employed the measurements of magnetic susceptibility and hysteresis, electrical conductivity, total dissolved solids, power of hydrogen (pH), particle morphology, and element contents that were statistically analyzed to identify relevant properties. The result was able to differentiate volcanic soils from urban, industrial, and agricultural areas as well. The value of low-frequency magnetic susceptibility (χLF) in soils from urban areas is higher than 866.0±249.9 ×10-8 m3 kg-1, while the value of χLF in agricultural areas is 208.0±67.8 ×10-8 m3 kg-1. This is reinforced by the relationship between low-frequency and frequency-dependent magnetic susceptibility (χLF-χFD%) in samples from urban areas that fall within the same cluster dominated by coarse-grained magnetic minerals originating from anthropogenic processes. In contrast, the agricultural area forms a separate cluster primarily influenced by pedogenic processes from acid igneous rock minerals. Caution is required for interpreting the magnetic signal due to the high contents of lithogenic magnetic particles inherited from the parent materials of Andisols.

Distribution of magnetic susceptibility of surface dust in Xining City and its indicative significance to heavy metal pollution

The establishment of heavy metal pollution grade standards based on the magnetic susceptibility of surface dust can provide a simpler magnetic method for the evaluation of heavy metal pollution of surface dust. A total of 251 urban soil surface samples were collected in Xining City, and As, Cd, Cr, Cu, Ni, and Pb were determined V and Zn contents, as well as low-frequency magnetic susceptibility (χLF) and high-frequency magnetic susceptibility (χHF). The common Kriging interpolation method was used to explore the spatial distribution of χLF, and the pollution load index (PLI) was used to evaluate the degree of soil heavy metal pollution, and the correlation analysis between PLI and χLF was established。 The results showed that the average PLI of the seven heavy metals in the urban soil samples of Xining City was 2 34. Moderate pollution, Zn is the most important pollution factor. The average value of soil χLF was 125. 7 × 10-8m3 kg-1, which decreased from “northwest-southeast”, and the high-value area appeared in the northwest near Xining Special Steel along the line. The regression equation between soil heavy metal PLI and χLF was y=3.36E-06x2+0.01x+0.9092, showing a significant positive correlation (p<0.01). The χLF of surface dust can be used to evaluate the degree of heavy metal pollution of surface dust in Xining City: when the χLF of surface dust is ≤66.05 × 10-8m3 kg-1, it is pollution-free; When 66.05 × 10-8m3 kg-1<χLF≤437.332 × 10-8m3 kg-1, it is slightly polluted. When 437.332 × 10-8m3 kg-1<χLF≤652.02 × 10-8m3 kg-1, it is moderately polluted. When χLF > 652.02 × 10-8m3 kg-1, it is an intensity pollution.

МАГНІТНО-МІНЕРАЛОГІЧНІ ВЛАСТИВОСТІ ҐРУНТІВ КИЇВЩИНИ, УРАЖЕНИХ ВІЙСЬКОВИМИ ДІЯМИ

Background. One of the dangerous effects on the environment caused by the military actions in Ukraine is the destruction of the soil. This includes its pollution, redistribution of genetic horizons, compaction, change of physical and chemical agronomic indicators, etc. Accumulated experience shows that most of these processes are reflected in the magnetic properties of soils. Methods. The applied magnetic method includes a full range of field and laboratory studies. More detailed magnetic mineralogical methods of measurements are described in. Results. On the basis of the diagram developed for the ratios of anhysteretic magnetic susceptibility to low-frequency magnetic susceptibility (χARM/χlf) and anhysteretic magnetic susceptibility to the frequency dependence of magnetic susceptibility (χARM/χfd), fine-grained magnetic particles of lithogenic and bacterial origin were detected in the soils of experimental areas of Kyiv region. For Stari Petrivtsi, only one group of samples was mainly identified. In Demydiv, we found two groups: a larger one, marked in green, and a smaller one, marked in red. Finally, two equivalent groups were identified in the Ozera study site. According to the results of the thermomagnetic analysis of magnetic susceptibility, an unusual "tail" for soils was identified after 600 °C, which indicates the content of metallic iron. The content of heavy metals in the magnetic extraction of soils from objects of military defeat depends on the composition of the alloys of the weapons striking a specific place. Conclusions. During the explosion of various types of ammunition, fragments of irregular shape are formed due to strong mechanical impact, and additional heating in the process leads to the formation of iron spherules. This complex physico-chemical process occurs as a result of the interaction of high-temperature gases, dust and molten metal. These objects are successfully identified by quick and cheap magnetic methods.

Soil organic carbon induces a decrease in erodibility of black soil with loess parent materials in northeast China

Abstract Although black soil in northeast China undergoes severe erosion, the contribution of parent materials, mainly Quaternary loess and non-loess sediments, to soil erodibility remains unclear. Considering the inheritance of ferromagnetic materials by parent materials, changes in magnetic parameters can successfully determine soil erodibility on a regional scale with a close climatic background. Here, we analysed the magnetic indicators of 142 samples from the black soil horizon formed on loess and non-loess sediments, covering areas of severe and slight erosion in the region to determine the effects of parent materials on the erodibility of black soil in northeast China. Both low-frequency magnetic susceptibility and frequency magnetic susceptibility (χfd) were proportional to the decrease in erosion rate due to erosion-induced leaching of ferromagnetic materials, and the change in χfd was narrow for black soil with loess parent materials, corresponding to relatively low soil erodibility. Compared with loess, the addition of soil organic matter could stabilise soils against erosion, thereby inducing a decrease in the erodibility of black soil formed on loess. Additionally, sustainable soil management policies to protect black soil from further erosion are necessary and urgent under the pressure of maintaining high grain yields and preventing erosion in northeast China.

Characteristics, sources, bio-accessibility, and health risks of organophosphate esters in urban surface dust, soil, and dustfall in the arid city of Urumqi in China

Sixty-eight paired samples of urban surface dust and soil as well as four samples of atmospheric dustfall were collected from the arid city of Urumqi in Northwest China. Thirteen organophosphate esters (OPEs) in these samples were analyzed for the characteristics, sources, bio-accessibility, and health risks of OPEs. The studied OPEs were widely detected in the urban surface dust, soil, and dustfall, with Σ13OPEs (total concentration of 13 OPEs) of 1362, 164.0, and 1367 ng/g, respectively, dominated by tris(2-chloroethyle) phosphate (TCEP), tri(2-chloroisopropyl) phosphate (TCiPP), tri(1, 3-dichloroisopropyl) phosphate (TDCiPP) and tris(2-butoxyethyl) phosphate (TBOEP), TBOEP and tri(2-ethylhexyl) phosphate (TEHP), and TCEP, TCiPP, TBOEP, triphenyl phosphate and TEHP, respectively. The low and high frequency magnetic susceptibility of surface dust and urban soil might indicate the pollution of OPEs in them. Elevated levels of the Σ13OPEs in the surface dust and urban soil were found in the west, south, and northeast of Urumqi city. The total deposition flux of dustfall-bound 13 OPEs ranged from 86.5 to 143 ng/m2/day, with a mean of 105 ng/m2/day. OPEs in the surface dust and urban soil were associated with the emissions of indoor and outdoor products containing OPEs, the dry and wet deposition of atmosphere, and the emissions of traffic. Trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tri-isobutyl phosphate, TCEP, TCiPP, TDCiPP, and TBOEP in surface dust and urban soil had relatively high bio-accessibility. The bio-accessibility of OPEs was mainly affected by the physio-chemical properties of OPEs. The non-cancer and cancer risks of human exposure to OPEs in surface dust and urban soil were relatively low or negligible. The current research results may provide scientific supports for prevention and control of pollution and risks of OPEs.

Magnetic Susceptibility and Hydrogen Cyanide Levels as Proxy Indicator for Gold Mining Pollution in River Sediment

Sumbawa’s Kuris River is one of the rivers contaminated by the island’s traditional gold mine. In order to detect contaminant levels, we examine the magnetic susceptibility, HCN levels, and the heavy metal contents on the river’s surface sediment. Environmental pollution has been widely assessed using a combination of magnetic properties and geochemical analysis. The goals of this research are to discover how magnetic susceptibility (χ) can be used as a first-order proxy for pollution. The relation between susceptibility and HCN is of particular interest, as this is a major contaminant associated with gold mining. The surface sediment samples were collected at ten different locations along the rivers. The magnetic susceptibility was determined using the Bartington MS2B, and the hydrogen cyanide (HCN) concentration was determined using Argentometric titration. The element content was determined by an Atomic Absorption Spectrometer (AAS). The low-frequency magnetic susceptibility (χlf) ranges from 71 to 115×10-8 m3/kg, with an average of 97×10-8 m3/kg, and the χfd(%) analysis ranges from 2% to 4%. The presence of spherical iron oxides, which are indicative of combustion byproducts, was also confirmed by SEM. The samples have low magnetic susceptibility but high levels of Hg and HCN. AAS results showed high Fe, Zn, and Cu concentrations in river sediments, with more variable concentrations of Hg, Mn, As, Cr, and Au. Because Fe, Cu, As, Hg, and HCN have a significant Pearson’s correlation with χfd(%), this parameter can be a useful indicator for contamination caused by gold mining waste.

Particulate phosphorus in runoff in a Mediterranean agroforestry catchment driven by land use and rainfall characteristics

AbstractThis study examined phosphorus (P) delivery and transport in flood events in an agroforestry catchment, with cropland and forestland as the main land uses. Sediments were collected in artificial‐lawn mats (MATs) distributed in five locations across the catchment (MAT1 to MAT5) along 20 seasonal campaigns during 5 years, in which rainfall with different characteristics was recorded. The properties analyzed in the surface soils under different land uses, and in the MATs used for collecting sediments included particle size and other properties such as soil organic matter (SOM), low frequency magnetic susceptibility (χLF) and P and Ti concentrations. The rainfall characteristics of the events recorded in each campaign were analyzed and the campaigns were grouped using cluster analysis taken into account the characteristics of the sediments collected. There was a P enrichment in the sediments compared to the sediment sources. The greatest P concentration was associated to sediment rich in clay and SOM. However, the sediment showed lower χLF, which could be due to higher erosion rates from the most degraded soils. The highest P losses were recorded at the catchment outlet, where the surface occupied by croplands was higher, with P values around 1.3 × times higher than at the headwaters. The differences between monitoring campaigns were attributed to differences in precipitation patterns that influence the hydrological response. The higher P concentration in the sediment during the campaigns that accumulated higher amount of rainfall in shorter periods of time confirmed the direct influence of rainfall intensity on the P mobilization.

Effect of land use conversion on heavy metals and magnetic minerals on water reservoir riparian soils

Spatial hydrological alterations seem to influence the variability of soil-bound magnetic particles and heavy metals in water reservoir riparian wetlands (RW). To date, applying geochemical analysis with magnetic techniques to assess heavy metal pollution is rarely practiced in RW soils. We studied the magnetic properties and heavy metals, including Cu, Cr, and Zn, of topsoils in RW and the adjacent upland regions (UR, as control) in the Three Gorges Reservoir, China. Potentially elevated low-frequency mass magnetic susceptibility (χLF), anhysteretic remanent magnetization susceptibility (χARM), isothermal remanent magnetism, and all selected heavy metals were found in RW. The grain size of the magnetic minerals was coarser in RW than that in UR. The pollution load index (PLI) of the studied samples was 1.18 ± 0.12 and 1.04 ± 0.21 in RW and UR, respectively. PLI and concentrations of Cu, Cr, and Zn were positively correlated with χLF, χARM, and isothermal remanent magnetism in RW, whereas no clear linkages were observed between PLI and isothermal remanent magnetism in UR. This finding reveals that hydrological alterations increased the magnetic enhancement and heavy metal enrichment in RW. We find that magnetic proxies of soils could trace the concentration of selected anthropogenic heavy metals and their pollution level in RW.

The Influence of Annealing and Film Thickness on the Specific Properties of Co40Fe40Y20 Films

Cobalt Iron Yttrium (CoFeY) magnetic film was made using the sputtering technique in order to investigate the connection between the thickness and annealing procedures. The sample was amorphous as a result of an insufficient thermal driving force according to X-ray diffraction (XRD) examination. The maximum low-frequency alternate-current magnetic susceptibility (χac) values were raised in correlation with the increased thickness and annealing temperatures because the thickness effect and Y addition improved the spin exchange coupling. The best value for a 50 nm film at annealing 300 °C for χac was 0.20. Because electron carriers are less constrained in their conduction at thick film thickness and higher annealing temperatures, the electric resistivity and sheet resistance are lower. At a thickness of 40 nm, the film's maximum surface energy during annealing at 300 °C was 28.7 mJ/mm2. This study demonstrated the passage of photon signals through the film due to the thickness effect, which reduced transmittance. The best condition was found to be 50 nm with annealing at 300 °C in this investigation due to high χac, strong adhesion, and low resistivity, which can be used in magnetic fields.

Co40Fe40Y20 Nanofilms’ Structural, Magnetic, Electrical, and Nanomechanical Characteristics as a Function of Annealing Temperature and Thickness

To investigate the correlations between different thicknesses and heat treatments, this study used a sputtering method to create CoFeY films. The results of X-ray diffraction (XRD) revealed the appearance of oxide peaks at 2θ = 47.7°, 54.5°, and 56.3° in agreement with YFeO3 (212), Co2O3 (422), and Co2O3 (511), respectively. The findings also demonstrated a relationship between the low-frequency alternative-current magnetic susceptibility (χac) values and the thickness of the CoFeY thin films. At a thickness of 50 nm and an annealing temperature of 300 °C, the ideal value of ac was 0.159. The presence of Y and the thickness impact were both evident in the χac value, which improved spin-exchange coupling as well as grain refining. With increasing thickness, the resistance decreased. At 300 °C and 40 nm in thickness, this film has a maximum surface energy of 31.2 mJ/mm2. The hardness of the 50-nm films reached a maximum of 16.67 GPa when annealed at 100 °C. Due to the high χac, strong adhesion, good nanomechanical properties, and low resistivity, the optimal conditions were determined to be 50 nm with annealing at 300 °C.

The Influence of Oxidation on the Magnetic, Electrical, and Mechanical Properties of Co40Fe40Yb20 Films

A typical body-centered cubic (BCC) CoFe(110) peak was discovered at approximately 2θ = 44.7°. At 2θ = 46°, 46.3°, 47.7°, 55.4°, 54.6°, and 56.4°, the Yb2O3 and Co2O3 oxide peaks were visible in all samples. However, with a heat treatment temperature of 300 °C, there was no typical peak of CoFe(110). Electrical characteristics demonstrated that resistivity and sheet resistance reduced dramatically as film thickness and annealing temperatures increased. At various heat treatments, the maximum hardness was 10 nm. The average hardness decreased as the thickness increased, and the hardness trend decreased slightly as the annealing temperature was higher. The highest low-frequency alternative-current magnetic susceptibility (χac) value was discovered after being annealed at 200 °C with 50 nm, and the optimal resonance frequency (fres) was discovered to be within the low-frequency range, indicating that the Co40Fe40Yb20 film can be used in low-frequency applications. The maximum saturation magnetization (Ms) was annealed at 200 °C for 50 nm. Thermal disturbance caused the Ms to decrease as the temperature reached to 300 °C. The results show that when the oxidation influence of as-deposited and thinner films is stronger than annealing treatments and thicker thickness, the magnetic and electrical properties can be enhanced by the weakening peak of the oxide, which can also reduce interference.

Effect of Annealing and Thickness of Co40Fe40Yb20 Thin Films on Various Physical Properties on a Glass Substrate.

The aim of this work is to investigate the effect of annealing and thickness on various physical properties in Co40Fe40Yb20 thin films. X-ray diffraction (XRD) was used to determine the amorphous structure of Co40Fe40Yb20 films. The maximum surface energy of 40 nm thin films at 300 °C is 34.54 mJ/mm2. The transmittance and resistivity decreased significantly as annealing temperatures and thickness increased. At all conditions, the 10 nm film had the highest hardness. The average hardness decreased as thickness increased, as predicted by the Hall-Petch effect. The highest low-frequency alternative-current magnetic susceptibility (χac) value was discovered when the film was annealed at 200 °C with 50 nm, and the optimal resonance frequency (ƒres) was in the low frequency range, indicating that the film has good applicability in the low frequency range. At annealed 200 °C and 50 nm, the maximum saturation magnetization (Ms) was discovered. Thermal disturbance caused the Ms to decrease when the temperature was raised to 300 °C. The optimum process conditions determined in this study are 200 °C and 50 nm, with the highest Ms, χac, strong adhesion, and low resistivity, which are suitable for magnetic applications, based on magnetic properties and surface energy.

Abundance and characteristics of sediment-bound magnetic minerals and trace elements in karst ditch wetland: A case study from Guizhou Province, China

This study investigated sediment-bound magnetic properties and selected trace elements level in the karst ditch wetland, Caohai National Nature Reserve, Guizhou Province, China. Sediment-bound magnetic signals were quantified using low-frequency mass magnetic susceptibility (χLF), anhysteretic remanent magnetization susceptibility (χARM), saturation isothermal remanent magnetization (SIRM), and percentage frequency-dependent susceptibility (χfd%). Concentrations of Cd, Cr, Sb and Zn were determined using inductively coupled plasma mass spectrometry. Sediment χLF, χARM, SIRM, and χfd% were higher than those of bedrocks and mainly altered by the pedogenic processes. The estimated χfd% ranged from 6.15 % to 14.62 % and reflected the magnetic grain sizes were largely concentrated in the range of superparamagnetic particles. The elevated concentrations of sediment-bound Cd, Cr, Sb, and Zn supported the significant contribution of the anthropogenic sources in the karst ditch wetlands. The weak relationship between magnetic signals and selected trace elements (p < 0.05) suggested the occurrence of few sediment-bound iron-containing minerals associated with selected trace elements. These results indicated that a minor contribution of anthropogenic sources of selected trace elements to the elevated sediment magnetic signals in the karst ditch wetlands.

Annealing effect on the structure, magnetic characteristic, surface energy and optical property of Co40Fe40W10B10 thin films

X-ray diffraction indicated an amorphous state of all annealed films, indicating that boron in CoFeW films could refine grain size and low annealing temperatures did not induce sufficient thermal driving force to support grain growth. The saturation magnetization (Ms) and low-frequency alternate-current magnetic susceptibility (χac) increased with the increase in the thicknesses and annealing temperatures, indicating the thickness effect and magneto-nanocrystalline anisotropy. The highest Ms and χac values of Co40Fe40W10B10 films were estimated to be 1233 emu/cm3 and 2.8, at an annealing temperature of 350 °C and thickness of 100 nm. Surface energy increased with the increase in thickness and annealing temperature. The highest surface energy of 100 nm thick Co40Fe40W10B10 film was 38.52 mJ/mm2 at 350 °C. The Co40Fe40W10B10 film had the highest transmittance when annealing temperature was 200 °C and 10 nm, and its transmittance rate was 32.7%. The transmittance decreased with the increase in thickness and annealing temperatures, while a higher thickness may inhibit the transfer of photon signals through the film, causing a low transmittance. In this study, the optimal condition of magnetic and adhesive properties of Co40Fe40W10B10 film was found to be 100 nm with annealing at 350 °C due to high Ms, large χac, and strong adhesion.

The use of space on two Early Iron Age house sites in South-West Jutland, South Scandinavia: A geoarchaeological multiproxy approach

This paper describes analyses for understanding the general use of space on two Early Iron Age house sites on the site of Sønderris in South-West Jutland (South Scandinavia). The main method consists of the geoarchaeological techniques of soil P analysis by citric acid extraction, low frequency magnetic susceptibility analysis, and measurement of the soils organic content by loss-on-ignition. The results of these analyses are, moreover, interpreted alongside artefact distribution data, data on the dispersal of plant macrofossils, and an evaluation of the architectural details of the sites.At both house sites, the geoarchaeological data shows patterning indicative of human activities. The main achievements are inference of outdoor areas which may have contained pyres or kilns, delineation of yard spaces with refuse deposition, and the characterisation of functional aspects of two small outbuildings. In general, the geoarchaeological results are consistent with the inferences attained from non-geoarchaeological sources. A notable exception is that few clear traces of stalling were identified in the geoarchaeological record, despite the presence of animal booth partition walls indicating the presence of byres in the longhouses. Possible reasons for this are discussed.Overall, this study demonstrates the continued usefulness of long-established geoarchaeological methods for gaining insights about the nature, extent, and orientation of activities on prehistoric house sites. A key take-away from the study is that the potential of any individual method for reading activities (geoarchaeological or otherwise), increases when several techniques with overlapping, but not identical, scope for inferring activities are integrated. The resulting multiproxy analysis is, as a whole, more useful than the sum of its constituent parts.

Magnetic Properties of Ancient Sediments Bengawan Solo, Central Java-East Java, Indonesia

Information about the eruption of Mount Lawu in Central Java Province in 1885 and Mount Merapi in D.I. Yogyakarta in 2010 became a source for estimating the presence of magnetic minerals which underwent a sedimentation process in the Bengawan Solo River from upstream (Wonogiri) - downstream (Bojonegoro). The results we get of the magnetic susceptibility distribution of the Bengawan Solo sediments reveal that the sediment from the upper reaches of the Bengawan Solo River has a low frequency magnetic susceptibility value in upstream of around 1,080.23×10−8 m3/Kg - 2,780.77×10−8 m3/Kg, the middle part is 74.40×10−8 m3/Kg - 1,735.90×10−8 m3/Kg, and downstream 17.57×10−8 m3/Kg - 1,620.53×10−8 m3/Kg. The value of magnetic susceptibility decreased significantly from upstream to downstream. High susceptibility indicates the sample contains metal elements. In determining iron oxide, we use X-Ray Fluorescence assisted by X-Ray Diffractometer testing to determine magnetic minerals. X-Ray Fluorescence confirm metal oxide in the sample. There are Al and Fe confirm the presence of magnetic properties in sedimentation. The Vibrating Sample Magnetometer confirmed that the Bengawan Solo sediment has a magnetic saturation about 0.06 - 9.50 (emu/g), a magnetic remanent around 0.001 - 0.575 (emu/g) and coercivity field of around 10 - 60.15 (Oe). X-Ray Diffractometer pattern confirm the mineral structures, namely Coesite, Magnetite, Cristobalite, Portlandite, Quartz, Anatase, Goethite, Tridymite, Gibsyte, Stishovite, Grasullaria, Labradorite and Wuestite. These results indicate the novelty of sediments from Bengawan Solo, Central Java to East Java. HIGHLIGHTS We found several important points in this research: The Bengawan Solo River is formed from several formations and lifting from faults The Bengawan Solo River is rich in minerals formed from metal oxides The magnetic value decreases with the distance from Mount Lawu The Bengawan Solo River has confirmed ferromagnetic properties from the S-type hysterisis curve With low magnetic remanent values, low saturation magnetism and high magnetic corrosivity GRAPHICAL ABSTRACT

Yttrium addition and annealing effect on the structural, magnetic, adhesive, and optical properties of CoFeY thin films on glass substrate

Co60Fe20Y20 film was sputtered on glass substrate with a 10 nm to 50 nm under four annealed conditions and the structure, magnetic properties, surface energy, and optical property were examined. An amorphous structure of CoFeY films was revealed by an X-ray diffraction analyzer, suggesting that the addition of yttrium (Y) refined the grain size and the annealing temperatures were insufficient to support grain growth. The saturation magnetization (Ms) and low-frequency alternate-current magnetic susceptibility (χac) increased with the increase in the thicknesses and annealing temperatures, suggesting that the thickness effect and Y can refine grain size and induce ferromagnetic spin exchange coupling. The highest Ms and χac of Co60Fe20Y20 film were 735 emu/cm3 and 0.23 at an annealing temperature of 300 °C and 50 nm. The χac value of CoFeY film decreased significantly with the increase in measured frequency, while the maximum χac value increased significantly after heat treatment. The optimal resonance frequency (fres) corresponding to the maximum χac was 50 Hz, indicating the applicability of the film in a low-frequency range. The highest surface energy of the 50 nm was 31.84 mJ/mm2 at 300 °C, while the highest transmittance 58% was observed in as-deposited 10 nm film. The transmittance decreased with the increase in annealing temperatures and thickness. A higher thickness may inhibit photon signal transfer through the film, causing a low transmittance. Moreover, the specific properties of Co60Fe20Y20 films are compared with Co40Fe40B10Y10 films, which indicate that Co60Fe20Y20 films have high maximum χac, surface energy, and transmittance than Co40Fe40B10Y10 films.

Annealing Effect on the Characteristics of Co40Fe40W10B10 Thin Films on Si(100) Substrate.

This research explores the behavior of Co40Fe40W10B10 when it is sputtered onto Si(100) substrates with a thickness (tf) ranging from 10 nm to 100 nm, and then altered by an annealing process at temperatures of 200 °C, 250 °C, 300 °C, and 350 °C, respectively. The crystal structure and grain size of Co40Fe40W10B10 films with different thicknesses and annealing temperatures are observed and estimated by an X-ray diffractometer pattern (XRD) and full-width at half maximum (FWHM). The XRD of annealing Co40Fe40W10B10 films at 200 °C exhibited an amorphous status due to insufficient heating drive force. Moreover, the thicknesses and annealing temperatures of body-centered cubic (BCC) CoFe (110) peaks were detected when annealing at 250 °C with thicknesses ranging from 80 nm to 100 nm, annealing at 300 °C with thicknesses ranging from 50 nm to 100 nm, and annealing at 350 °C with thicknesses ranging from 10 nm to 100 nm. The FWHM of CoFe (110) decreased and the grain size increased when the thickness and annealing temperature increased. The CoFe (110) peak revealed magnetocrystalline anisotropy, which was related to strong low-frequency alternative-current magnetic susceptibility (χac) and induced an increasing trend in saturation magnetization (Ms) as the thickness and annealing temperature increased. The contact angles of all Co40Fe40W10B10 films were less than 90°, indicating the hydrophilic nature of Co40Fe40W10B10 films. Furthermore, the surface energy of Co40Fe40W10B10 presented an increased trend as the thickness and annealing temperature increased. According to the results, the optimal conditions are a thickness of 100 nm and an annealing temperature of 350 °C, owing to high χac, large Ms, and strong adhesion; this indicates that annealing Co40Fe40W10B10 at 350 °C and with a thickness of 100 nm exhibits good thermal stability and can become a free or pinned layer in a magnetic tunneling junction (MTJ) application.