Ferromagnetic Signal Research Articles

Simple hysteresis loop model for rock magnetic analysis

A simple phenomenological model founded on Lorentzian functions is evaluated on the first derivative of magnetic hysteresis loops from several artificial samples with iron oxide/oxyhydroxide mixtures imitating natural sediments. The approach, which shows that hysteresis loops can be described by elementary analytical functions and provides estimates of magnetization parameters to a satisfactory degree of confidence, is applied with the help of standard data analysis software. Distorted hysteresis loops (wasp-waisted, goose-necked and pot-bellied shaped) from simulations and artificial samples from a previous work are reproduced by the model which allows to straightforwardly unmix the ferromagnetic signal from different minerals like magnetite, greigite, haematite and goethite. The analyses reveal that the contribution from the ferrimagnetic fraction, though present in a minor concentration (≤2.15 wt%), dominates the magnetization.

전기도금으로 제작한 니켈 나노튜브의 강자성 공명 신호 분석

전기도금으로 제작한 니켈 나노튜브의 강자성 공명 신호 분석

Magnetic properties of granulated [formula omitted][formula omitted]:Fe films with different structure of [formula omitted]-Fe nanoclusters

We report the modification of magnetic properties due to variation of the structure of Fe-contain granules in SiCxNy:Fe films grown by chemical vapor deposition at different temperatures from various gaseous mixtures. It was shown that formation of large composite Fe-granules in the case of structures created using hexamethyldisilazane as source of Si, C, and N atoms results in the hysteresis loop in the magnetization curve appeared only at low temperature (5 K). The ESR spectra are characterized by many ESR lines with sharp asymmetrical shapes and different line widths. The samples with a dense arrays of small homogeneously distributed α-Fe granules, obtained with hexamethylcyclotrisilazane, demonstrate the large saturation magnetization, the hysteresis loop (~135 Oe at 300 K and ~680 Oe at 5 K) and the collective ferromagnetic resonance signal. The pronounced magnetic properties are explained by the formation of the single magnetic domain due to quantum-mechanical tunneling between small coupled α-Fe clusters. Conductivity measurements confirm the existence of the tunneling coupling between Fe-granules even in case of lowest Fe concentration in the samples under study.

Magnetization signals in μm-thin lamellae of highly oriented pyrolytic graphite: a field-dependent study

The recent discovery of superconductive features in HOPG has attracted much interest. However, further investigations are needed in order to clearly elucidate the magnetization properties of these materials. In this letter we investigated the structural and magnetic characteristics of μm thin lamellae extracted from inner/central regions of HOPG (grade B, θmisfit-tilt ∼ 0.8°) by using exfoliation-methods. Unusual magnetic signals were detected in the lamellae extracted from inner-central-regions by SQUID-magnetometry. Instead ferromagnetic signals were detected on the HOPG surface layers. The field dependent characteristics of these signals were investigated. ZFC and FC measurements of superficial and inner lamellae of the HOPG sample revealed significantly different signals which may imply the existence of multiple magnetic components within the whole HOPG structure.

Role of Fe-Doping on Structural, Optical and Magnetic Properties of SnO2 Nanoparticles

We have investigated the influence of Fe doping (1 at.% and 2 at.%) on the structural, optical and magnetic properties of SnO2 nanoparticles (NPs) synthesized via co-precipitation route. Rietveld refinement of x-ray diffraction results confirmed the successful substitution of Fe ions into the SnO2 rutile crystal structure without secondary phase. The crystallite sizes increased with an increase in Fe concentration and were found to be in the range of 9–26 nm. Field-emission scanning electron microscopy results revealed that the doping of Fe ions enhances the agglomeration of the grains and consequently cluster formation takes place with uniformly dispersed spherical-like morphology. Hence, the statistical distributions of NP sizes were in the range of 20–25 nm and 40–60 nm for 1 at.% and 2 at.% Fe doping, respectively. Energy dispersive x-ray spectra confirmed the elemental ratios present in the samples. Raman spectral features elucidated that the variation in Fe concentration induces a change in the oxygen stoichiometry and enhances the formation of oxygen vacancies (Ov).The magnetization investigation showed that pure SnO2 is a nonmagnetic compound even in the presence of Ov that has been proven theoretically based on density functional theory calculations, whereas the Fe (1 at.% and 2 at.%)-doped SnO2 NPs showed a weak ferromagnetic signal. Our study confirmed that the FM in pure SnO2 NPs (d0-magnetization) is not possible and that the Fe dopant ions are responsible for the observed ferromagnetic state. The role of Fe doping and surface Ov has been discussed based on the bound magnetic polaron mechanism.

Investigation on versatile behaviour of Cd doped SrTiO3 perovskite structured compounds

Ferromagnetism induced by Cd ions in SrTiO3 with various x-values (x = 0, 0.01, 0.03, 0.05 wt%) was synthesized by solid state reaction. Powder XRD reveals the formation of cubic perovskite structure with space group pm3m of all the prepared compounds. FTIR confirms the metal oxide chemical bonding present in the samples. Raman spectra justify the formation of cubic perovskite structure and the presence of local disorder in the ceramics. Polydispersed behaviors of all the samples were observed through scanning electron microscope. The elemental composition of Sr, Ti, O and Cd were analysed through EDAX spectra. Visible range optical absorption was observed for the samples by UV–Visible studies then the optical bandgap values were estimated. Presence of multicolor such as violet, green and blue emission at an excitation of 330 nm in the PL spectra confirms the existence vacancies in the prepared samples. At room temperature, strontium titanate is diamagnetic, on addition of Cd in SrTiO3 lattice induces ferromagnetic signature. Hence, the induced ferromagnetic behavior of the doped samples may be understood in terms carrier mediated ferromagnetism.

Ferroelectric and Multiferroic Properties of Single-Phase Yb2NiMnO6 Double-Perovskites

Here we present the potential for single-phase Yb2NiMnO6 as a multiferroic 2D material with coupled ferroelectric/magnetic orders synthesized via solid-state reaction. Realistically large room- to elevated-temperature stable switching polarization reversal loops confirm the elevated temperature dense data bit storage material. Temperature-stable ferroelectricity and fine polarization recorded at room temperature and read at 200°C confirm elevated temperature dense data storage. The physics behind the coexistence of coupled orders is the focus of this work. Realistically large ferroelectric polarization loops produced at ±400 kV/cm confirm saturation polarization (PS) at around 20 μC/cm2. Microstructural and compositional analysis reveals that the ferromagnetic signature is generated from single-phase Yb2NiMnO6 with a confidence level of 99.95%. Rietveld refined x-ray diffraction reveals that Yb2NiMnO6 is a single-phase material displaying a GdFeO3-type orthorhombic structure with distorted (Ni/Mn)O6 (pnma; a = 5.5519 Ǻ; b = 5.1851 Ǻ; c = 7.4396 Ǻ; V = 214.18 Ǻ3). X-ray photoelectron spectroscopy confirms that Yb2NiMnO6 constituting the Mn2P3/2 core level appears at ∼642.2 eV and an Ni2P3/2 peak appears at ∼855.3 eV, displaying +4 and +2 valence states. Frequency dispersion and scaling behaviour in dielectric (e′) and dielectric loss (tanσ) indicate that the relaxation mechanism is independent of temperature. The σDC versus 1/T slope confirms that the hopping mechanism is responsible for charge carrier transport. The complex impedance reveals that the relaxation/conduction is the bulk effect arising from the semiconductor grains displaying grain resistance and capacitance with respect to temperature (113–363 K) and frequency (1–1 × 107 Hz). We have correlated and presented the effect of the microstructure on the electrical properties using an equivalent circuit (RgQg) (RgbQgb) (RcQc) at low temperature and changing to (RgbQgb) (RcQc) on high temperature. MS, HC and MR extracted from the ferromagnetic hysteresis loop are 11.75 emu/g, 180 Oe and 4.15 emu/g at room temperature (300 K). The zero-field-cooled and field-cooled magnetization (ZFC–FC) curve confirms the ferromagnetic nature. From these results, we show that Yb2NiMnO6 is multiferroic, with potential for application in four-state logic memory, ferroelectric random access memory and ferroelectric/magnetic sensors.

Role of Co dopants on the structural, optical and magnetic properties of lead-free ferroelectric Na0.5Bi0.5TiO3 materials

Abstract Co-doped Na0.5Bi0.5TiO3 materials were fabricated by a sol-gel technique. The structural distortion of Co-doped Na0.5Bi0.5TiO3 materials was due to the difference between the radii of Co dopants and Ti hosts. The optical band gap decreased from 3.11 to 1.83 eV because of the local state of the Co cation in the band structure. Room temperature ferromagnetism emerged as compensation of diamagnetic background and possibly intrinsic ferromagnetic signals. The magnetic moment was determined to be ∼0.64 μB/Co at 5 K. The origin of the room temperature ferromagnetism in the Co-doped Na0.5Bi0.5TiO3 materials was also investigated through the first-principles calculation method. Our study provides physical insights into the complex magnetic nature of transition metal-doped ferroelectric perovskites and contributes to the integration of multifunctional materials into smart electronic devices.

Magnetic-field-induced ferroelectric domain dynamics and in-plane polarization in odd and mixed layered Aurivillius structures

Herein, we conclusively discovered the role of “2D” odd/mixed, layered Aurivillius structures in generating coupled order parameters by directly visualizing magnetic-field-induced ferroelectric switching. We developed a novel sequence liquid injection-chemical vapor deposition process to fabricate atomistically controlled layer-by-layer genuine multiferroic Bi6Ti2.9Fe1.5Mn0.6O18 and Bi6Ti2.7Fe1.5Mn0.8O18 thin films. Ferromagnetic signature (MS = 13.79 emu/cc, HC = 9 mT at 300 K, and MR = 8 emu/cc) was generated for Bi6Ti2.9Fe1.5Mn0.6O18 thin films; however, no response was observed for mixed m = 5/6 intergrowths in Bi6Ti2.7Fe1.5Mn0.8O18 films. In-plane PR with magnetic (Fe/Ti)/conducting (Au/Ti) for Bi6Ti2.9Fe1.5Mn0.6O18 thin films is less (±23.66–24.69 μC/cm2) than the mixed m = 5/6 Bi6Ti2.7Fe1.5Mn0.8O18 layer structure (±57.42–67.94 μC/cm2). High leakage current for Fe/Ti interdigital capacitors (IDCs) compared to Au/Ti IDCs samples confirms Au/Ti IDCs’ suitability for ferroelectric industry. High ferro-paraelectric transition (Tc = 850 K), excellent in-plane polarization with negligible fatigue (9% after 1010 switching cycles), and coupled magnetoelectric (ME) (10% in-plane and 13% out-of-plane) orders provide an important contribution in a high-temperature fatigue free nonvolatile in-plane FeRAM, 4-state logics, and ME sensors. This article is being retracted effective 16 November 2020.

Magnetic characterization of nano-sized terbium doped bismuth ferrite synthesized by sol-gel method

Abstract Bi(1−x)TbxFeO3 (x = 0, 0.03, 0.04, 0.06, 0.09, 0.12) nanoparticles are prepared by sol-gel method. X-ray diffraction analysis shows the formation of perovskite structure in the synthesized samples and crystallite sizes in the range of 15 nm. The perovskite structure together with the presence of a strong absorption peak observed at 545 cm−1 in the Fourier Transform Infrared Spectroscopy measurements, characteristic of FeO6 octahedral, confirms the formation of single phase BiFeO3 structure. The cycloidal spin nature of BiFeO3 is said to be suppressed in particles that are less than 62 nm across enhancing the ferromagnetic signature. The magnetic behaviour of the Bi(1−x)TbxFeO3 nanoparticles is found to change anomalously with change in Tb doping. Vibrating-sample magnetometer studies reveal a maximum in the magnetic moment for a Tb doping concentration of x = 0.03 with clear ferromagnetic order at room temperature. With increase in x beyond 0.03, magnetization decreases, while a further increase beyond x = 0.04 once again increases the magnetization. Room temperature Mossbauer spectroscopy reveals the presence of a paramagnetic doublet and a sextet, the variation of whose relative ratios is in corroboration with the magnetization studies.

Towards Laterally Resolved Ferromagnetic Resonance with Spin-Polarized Scanning Tunneling Microscopy.

We used a homodyne detection to investigate the gyration of magnetic vortex cores in Fe islands on W(110) with spin-polarized scanning tunneling microscopy at liquid helium temperatures. The technique aims at local detection of the spin precession as a function of frequency using a radio-frequency (rf) modulation of the tunneling bias voltage. The gyration was excited by the resulting spin-polarized rf current in the tunneling junction. A theoretical analysis of different contributions to the frequency-dependent signals expected in this technique is given. These include, besides the ferromagnetic resonance signal, also signals caused by the non-linearity of the characteristics. The vortex gyration was modeled with micromagnetic finite element methods using realistic parameters for the tunneling current, its spin polarization, and the island shape, and simulations were compared with the experimental results. The observed signals are presented and critically analyzed.

The effect of oxidation on the mineralogy and magnetic properties of olivine

Although nucleation of magnetite and/or hematite along dislocations upon oxidation of olivine has been observed by many workers, the effect of oxidation on the magnetic properties of the sample with specific mineralogical alterations has not been studied. Therefore, we investigate this problem using a set of time series 1 bar oxidation experiments at 600 and 900 °C. Results show rapid olivine oxidation and alteration at both 600 and 900 °C, forming magnetite and hematite associated with a change from paramagnetic to ferromagnetic behavior after oxidation. Magnetite and hematite nucleate along dislocations and impurities in the crystal structure, along with surface coatings and within cracks in the crystals. Fresh, unaltered mantle xenoliths containing magnetite have been interpreted as having formed in cold tectonic regimes in the mantle, rather than through oxidation during or after ascent. Mantle xenoliths rapidly ascend through the mantle with estimates of the ascent of up to 90 km/h (3 GPa/h) based on the diffusion profile of water in mantle olivine. The rates correspond to xenoliths ascending through the mantle over hours and not days or weeks. Our results show that olivine oxidation and alteration can occur in days to weeks at 600 °C and within minutes at 900 °C. Therefore, if the xenolithic material is transported to the surface in a cold magma (at temperatures ≤600 °C), then the timescale of ascent is likely not long enough for oxidation to cause magnetite formation or a ferromagnetic signature to occur. However, if the material is transported in a hot oxidized basaltic magma (with temperatures ≥900 °C), then oxidation can cause magnetite formation and a ferromagnetic signature.

High-pressure magnetism of the double perovskite Sr2FeOsO6 studied by synchrotron Fe57 Mössbauer spectroscopy

The pressure dependence of the magnetism of the double perovskite ${\mathrm{Sr}}_{2}{\mathrm{FeOsO}}_{6}$ was investigated by temperature- and magnetic-field-dependent synchrotron $^{57}\mathrm{Fe}$ M\ossbauer spectroscopy in the energy domain up to $\ensuremath{\sim}50$ GPa. ${\mathrm{Sr}}_{2}{\mathrm{FeOsO}}_{6}$ is known to feature antiferromagnetic ordering below ${T}_{\mathrm{N}}\ensuremath{\sim}140$ K and a change in spin structure from AF1 to AF2 near 70 K at ambient pressure. Previous Os ${L}_{2,3}$ x-ray magnetic circular dichroism (XMCD) spectra [Veiga et al., Phys. Rev. B 91, 235135 (2015)] indicated a pressure-driven change from the antiferromagnetic to the ferrimagnetic state. Raman spectra of ${\mathrm{Sr}}_{2}{\mathrm{FeOsO}}_{6}$ collected at room temperature and up to 34 GPa are in agreement with previous x-ray-diffraction studies which verified that the tetragonal ambient pressure crystal structure is retained at high pressure. The M\ossbauer investigations show that the Fe ions remain in the +3 high-spin $({{t}_{2g}}^{3}{e}_{g}^{2})$ state over the whole pressure range. The magnetic ordering is strongly stabilized by high pressure and for $pg30$ GPa the ordering temperature is increased to above room temperature. Broad magnetic hyperfine patterns as well as coexistence of magnetic and paramagnetic signals at high pressures indicate the formation of inhomogeneous magnetic states. The shapes of applied-field M\ossbauer spectra at low temperature are similar at 2 and 33 GPa and do not allow resolution of distinct antiferromagnetic and ferrimagnetic components. Pressure-induced spin canting in a basically antiferromagnetic spin structure or magnetic phase separation involving a pressure-induced minority ferrimagnetic phase may be the origin for the ferromagnetic XMCD signal.

Magnetic Silicium Hydroxyapatite Nanorods for Enhancing Osteoblast Response in Vitro and Biointegration in Vivo.

Osteoblast behavior playing an important role in the biointegration of the Ti implant with host bone in vivo can be regulated by surface properties and magnetic field. In order to endow the Ti surface with good osteogenesis activity, Si monosubstituted and Fe and Si cosubstituted hydroxyapatite (HAp) nanorods were fabricated on microporous TiO2 by microarc oxidation (MAO) followed with hydrothermal treatment (HT). The surface properties including microstructure, microroughness, hydrophilicity, ion release, magnetic property, cytocompatibility, and biointegration of substituted HAp nanorods were observed and evaluated, together with pure HAp nanorods and microarc oxidated (MAOed) TiO2 as controls. After being doped with Fe, MAOed TiO2 has no changes in phase composition and microroughness, whereas it displays weakly ferromagnetic behavior and can enhance osteoblast differentiation in vitro and formation of new bone in vivo, compared with the undoped one. The substituted HAp nanorods adhere firmly to TiO2 and have almost the same wettability and microroughness but additional Si, Fe, and/or Ca released into the medium, compared with pure HAp nanorods. Moreover, the cosubstituted HAp has a small ferromagnetic signal, while its saturation magnetization value is less than that of the MAOed doped with Fe. Compared to pure HA nanorods, the substituted HAp nanorods not only improve cell proliferation and differentiation in vitro, but also enhance the ability of bone integration in vivo, especially for the cosubstituted one, which should be ascribed to the combined effect of microstructure, magnetic property, and released ions.

Structural, Spectroscopic, and Magnetic Studies on Copper Tartrate Crystals

Abstract Copper tartrate crystals were grown by the gel growth method and characterised by energy-dispersive X-ray (EDAX), scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, Fourier transform infrared, photoluminescence (PL), electron paramagnetic resonance, and low-temperature magnetic studies in the temperature range 300–20 K. The XRD study confirmed the orthorhombic structure of the crystal and the XPS study established the Cu2+ ions in the crystal. UV-vis study deduced the energy gap as 2.15 eV, confirming the semiconducting nature, and Urbach energy as 0.4686 eV. PL showed the presence of Cu2+ vacancy-related defects. Low-temperature magnetic study confirmed the paramagnetic nature in the temperature range 300–77 K, and the crystal showed a weak ferromagnetic signal at 20 K, which is interesting. The magnetic field along with the low temperature caused an ordered spin orientation.

Investigation of ferromagnetic resonance and damping properties of CoFeB

In this study, the influences of thin film thickness and post-annealing process on the magnetic properties of CoFeB thin films were investigated. The angular dependency and linewidth of the ferromagnetic resonance signal were used to explore the magnetic behavior of sputtered single-layer and trilayer thin film stacks of CoFeB. A micromagnetic simulation model was employed based on the metropolis algorithm comprising the demagnetizing field and in-plane induced uniaxial anisotropy terms with all relevant contributions. Our results reveal that the direction of magnetization changes from in-plane to out-of-plane as a result of the annealing process and induces a perpendicular magnetic anisotropy in the 1-nm thick CoFeB thin film. The ferromagnetic resonance (FMR) linewidth can be defined well by the intrinsic Gilbert damping effect and the magnetic inhomogeneity contribution in both as-grown and annealed samples. The difference between the linewidths of the single and trilayer film is mainly caused by the spin pumping effect on damping which is associated with the interface layers.

Detection of the Sentinel Node Using a Magnetic Tracer in Thyroid Cancer. A Technical Pilot Study

IntroductionThere is no standard procedure for the detection of the sentinel node (SN) in thyroid disease. However, the recent detection of the SN using a paramagnetic tracer is proving to be useful in breast cancer and melanoma. The objective was to assess the utility of super paramagnetic iron oxide tracer for the intraoperative detection of the SN in patients with papillary thyroid cancer without nodal involvement in the preoperative study. MethodA single center, prospective pilot study of a class IIa medical device (a paramagnetic tracer). The study included thyroid cancers which were T1–T2 tumors in the cytohistological analysis with a negative preoperative nodal assessment, operated on consecutively during scheduled treatment. For the localization of the SN, an interlesional injection of 2mL of super paramagnetic iron oxide was administered. After 10min, ferromagnetic activity was detected in the adjacent nodes. Once the node had been detected, we proceeded by extracting it for intraoperative analysis. The effectiveness of the procedure for detecting the SN was assessed, with the main variable being whether it was detected or not. ResultsThe project was assessed after the first cases had been carried out. The SN was located in all cases, which was done easily in the first four, but in the fifth case the SN detection was complicated by the interference of the reusable neurostimulation electrodes with the ferromagnetic signal. Intraoperative histology revealed the SN was positive in 80% (n=4) of cases (20% [n=1] were macrometastases and 60% [n=3] micrometastases). Total thyroidectomies were carried out, with central lymph node dissection in 4 of the patients and lateral in one due to the result of the detected SN. The histology showed the carcinoma was papillary, a classic type, in 80% (n=4) and a follicular variant in 20% (n=1). Forty percent (n=2) were multifocal, 40% (n=2) had vascular infiltration, and 60% (n=3) had extrathyroidal extension. Staging determined the application of radioactive iodine therapy (150mCi) in 80% of cases (n=4). ConclusionsA paramagnetic tracer can be useful for detecting the SN and correctly staging papillary carcinoma.

Detección del ganglio centinela mediante trazador paramagnético en el cáncer de tiroides. Estudio piloto técnico

IntroductionThere is no standard procedure for the detection of the sentinel node (SN) in thyroid disease. However, the recent detection of the SN using a paramagnetic tracer is proving to be useful in breast cancer and melanoma. The objective was to assess the utility of super paramagnetic iron oxide tracer for the intraoperative detection of the SN in patients with papillary thyroid cancer without nodal involvement in the preoperative study. MethodA single center, prospective pilot study of a class IIa medical device (a paramagnetic tracer). The study included thyroid cancers which were T1-T2 tumors in the cytohistological analysis with a negative preoperative nodal assessment, operated on consecutively during scheduled treatment. For the localization of the SN, an interlesional injection of 2mL of super paramagnetic iron oxide was administered. After ten minutes, ferromagnetic activity was detected in the adjacent nodes. Once the node had been detected, we proceeded by extracting it for intraoperative analysis. The effectiveness of the procedure for detecting the SN was assessed, with the main variable being whether it was detected or not. ResultsThe project was assessed after the first cases had been carried out. The SN was located in all cases, which was done easily in the first four, but in the fifth case the SN detection was complicated by the interference of the reusable neurostimulation electrodes with the ferromagnetic signal. Intraoperative histology revealed the SN was positive in 80% (n=4) of cases (20% [n=1] were macrometastases and 60% [n=3] micrometastases). Total thyroidectomies were carried out, with central lymph node dissection in 4 of the patients and lateral in one due to the result of the detected SN. The histology showed the carcinoma was papillary, a classic type, in 80% (n=4) and a follicular variant in 20% (n=1). Forty percent (n=2) were multifocal, 40% (n=2) had vascular infiltration, and 60% (n=3) had extrathyroidal extension. Staging determined the application of radioactive iodine therapy (150mCi) in 80% of cases (n=4). ConclusionsA paramagnetic tracer can be useful for detecting the SN and correctly staging papillary carcinoma.

Nonvolatile Electric‐Field Control of Ferromagnetic Resonance and Spin Pumping in Pt/YIG at Room Temperature

AbstractElectric‐field‐controlled magnetism is of importance in realizing energy efficient, dense and fast information storage and processing. Strain‐mediated converse magneto‐electric (ME) coupling between ferromagnetic and ferroelectric heterostructure shows promise for realizing electric‐controlled magnetism at room temperature and is attracting a number of recent investigations. However, such ME‐effect studies have mainly focus on magnetic metals. In this work, high quality yttrium iron garnet (Y3Fe5O12 (YIG)) films are deposited directly onto (100)‐oriented single‐crystal Pb (Mg1/3Nb2/3)0.7Ti0.3O3 (PMN‐PT) substrates by means of magnetron sputtering. The electric‐field‐induced polarization switching and lattice strain in the PMN‐PT substrate results in two distinct magnetization states in the YIG film that are nonvolatile and electrically reversible. Because of the direct contact between the YIG and the PMN‐PT substrate, an efficient ME coupling and an almost 90° rotation of the easy axis of the YIG film can be realized. Furthermore, the electric‐field‐controlled hysteresis loop‐like ferromagnetic resonance field shifts and spin pumping signals are observed in Pt/YIG/PMN‐PT heterostructures. Thus, the obstacle is overcome via growing high‐quality YIG thin films directly onto PMN‐PT substrates and an efficient manipulation of magnetism and pure spin current transport by electric field is thereby realized. These findings are instructive for future low‐power magnetic insulator‐based spintronic devices.

Investigation of local geometrical structure, electronic state and magnetic properties of PLD grown Ni doped SnO2 thin films

We have investigated the ferromagnetic behavior, electronic states and local geometrical structure of Ni (2 and 10 at %) doped SnO2 thin films. The films were successfully fabricated with the help of pulsed laser deposition (PLD) technique on Si (100) substrate under ultrahigh vacuum (UHV) condition. X-ray diffraction (XRD) results revealed the single phase character of SnO2 rutile lattice structure with P42/mnm space group. The inclusion of Ni ions into SnO2 matrix induced oxygen vacancy (Vo), enhanced the distortion in octahedral local symmetry and reduced the oxidation state of the host Sn4+ (SnO2) to Sn3+ (Sn2O3), these details have been estimated by Raman scattering, Near edge X-ray absorption fine structure (NEXAFS) spectra at Ni L3,2 and O K edges. Further quantitative details on the local geometrical structure around Ni ions were obtained via fitting the experimental Fourier transforms EXAFS spectra |X(R)| with FEFF6 code. The magnetization measurements performed at room temperature (RT) infers that Ni doped SnO2 films displayed ferromagnetic (FM) signal, and there was no significant difference in the saturation moments even with increase in the Ni content. Hence, the similarity in the observed magnetic behavior of the films seems relevant to the same crystal growth condition (UHV) and might not be limited directly to the Ni dopant concentrations. The FM signal and the role of surface defects have been discussed in the light of spin-split impurity band percolation mechanism.