Increase In Saturation Magnetization Research Articles

Energetic Electron-Assisted Synthesis of Tailored Magnetite (Fe3O4) and Maghemite (γ-Fe2O3) Nanoparticles: Structure and Magnetic Properties.

Iron oxide nanoparticles with a mean size of approximately 5 nm were synthesized by irradiating micro-emulsions containing iron salts with energetic electrons. The properties of the nanoparticles were investigated using scanning electron microscopy, high-resolution transmission electron microscopy, selective area diffraction and vibrating sample magnetometry. It was found that formation of superparamagnetic nanoparticles begins at a dose of 50 kGy, though these particles show low crystallinity, and a higher portion is amorphous. With increasing doses, an increasing crystallinity and yield could be observed, which is reflected in an increasing saturation magnetization. The blocking temperature and effective anisotropy constant were determined via zero-field cooling and field cooling measurements. The particles tend to form clusters with a size of 34 nm to 73 nm. Magnetite/maghemite nanoparticles could be identified via selective area electron diffraction patterns. Additionally, goethite nanowires could be observed.

Magnetic and structural properties of sputtered thick Co2FeSi alloy films

We investigate magnetic and structural properties of the sputtered thick Co2FeSi (CFS) alloy films. X-ray diffraction measurements show CFS alloy film changes from amorphous to disordered A2 structures after annealing, which leads to pronounced increase in saturation magnetization. For the as-deposited films in-plane uniaxial magnetic anisotropy is determined to be in the range of 103–104 erg/cm3, showing strongly dependent to film thickness. After annealing a fourfold cubic magnetic anisotropy is witnessed. Structural ordering is observed to improve with increasing film thickness. Similiar trend of the magnetic anisotropy with sputtering power is witnessed, which can be explained by equivalent annealing effect of the high-power sputtering. Our results show that magnetic anisotropy properties of the CFS alloy films are strongly dependent to film thickness and structural ordering, tuned by anealing tempeature and sputtering power. These findings may be helpful for designing Co2FeSi-based spintronic devices.

Interface-Mediated YIG/Ce:YIG Bilayers Structure with Enhanced Magneto-optical Properties via Pulsed Laser Deposition

For the realization of integrated nonreciprocal photonic devices for optical communication, on-chip monolithic integration of magneto-optical materials onto silicon remains a challenge. Implemented with pulsed laser deposition (PLD), a MgO interfacial layer is introduced to overcome the material incompatibilities between a silicon substrate and magneto-optical thin films of yttrium iron garnet (YIG). With a thickness of ∼40 nm, the amorphous interfacial layer of MgO can effectively inhibit interdiffusion across YIG/Si and promote the growth of a high-density, high-phase-purity polycrystalline garnet structure in the bilayer of YIG/Ce:YIG. Such modified chemistry and microstructure in YIG/Ce:YIG lead to enhanced magneto-optical properties, including an ∼38% increase in Faraday rotation and an ∼15% increase in saturation magnetization, as well as an ∼20% increase in infrared (IR) transmission. Offering dual functions of diffusion barrier and structure template, the MgO layer demonstrated herein suggests a new remedy solution to heterogeneous interfaces in advanced thin film devices.

The Role of Carbon Content: A Comparison of the Nickel Particle Size and Magnetic Property of Nickel/Polysiloxane‐Derived Silicon Oxycarbide

The Role of Carbon Content: A Comparison of the Nickel Particle Size and Magnetic Property of Nickel/Polysiloxane‐Derived Silicon Oxycarbide

Covalent surface modification of nickel ferrite nanoparticles for electrochemical supercapacitor performance

Modification of NiFe2O4 nanoparticles via aryl diazonium produces up to 160% increase in saturation magnetization and 190% increase in pseudocapacitance.

Atomic-scale observation of calcium occupation in spinel cobalt ferrite towards the regulation of intrinsic magnetic properties.

Spinel ferrites have drawn intensive attention because of their adjustable magnetic properties by ion doping, among which calcium (Ca) is an essential dopant that is widely employed in massive production. However, its exact lattice occupation and relationship with intrinsic magnetic properties remain unclear. Here, we successfully prepared Ca-doped cobalt ferrite (CoFe2O4) nanoparticles by electrospinning. Ca2+ is observed to occupy both the tetrahedral Fe site and the octahedral Co site using spherical aberration correction transmission electron microscopy (TEM) and prefers to occupy the octahedral site at a high doping level. Such dual occupation behavior affects the tetrahedral and octahedral sublattices differently, resulting in nonmonotonic saturation magnetization variation, reduced magnetocrystalline anisotropy and negative magnetization in the zero field cooling (ZFC) process. By controlling the Ca doping amount, increased saturation magnetization and reduced coercivity can be obtained simultaneously. Our findings establish the relationship between the atomic-scale structural change and the macroscopic magnetic properties of spinel ferrites, promoting the development of new ferrite materials.

Study on magnetic properties and microstructure of Fe0.18Co0.36Ni0.21Al0.10Cr0.15 high entropy alloy thin films

High entropy alloys (HEAs) based on magnetic elements (Fe, Co, Ni) are expected to show excellent soft magnetic properties and good electrical and mechanical properties. In this study, Fe0.18Co0.36Ni0.21Al0.10Cr0.15 HEA films of two different thicknesses (20 nm, 175 nm) have been prepared by magnetron sputtering method using pure metal targets. The magnetic measurements show that the as-deposited films have low saturation magnetization (247 emu/cm3) but increase with increasing annealing temperature. It shows a maximum value of 698 emu/cm3 when annealed at 800 ℃. At the same time, the coercivity (Hc) changes from 3 to 87 Oe. The XRD results have shown that the as-deposited films have a single-phase FCC (111) structure. With the increase of annealing temperature, the crystallinity becomes better, but there is no phase transformation. The transmission electron microscopy (TEM) results further confirmed the formation of a uniform FCC phase. Increasing the annealing temperature facilitates the growth of grains, which is the main reason causing the change of coercivity. Element mapping results have revealed that at room temperature, the distribution of the five elements is uniform, whereas after annealing at 400 ℃, Fe and Co slightly segregate. When the film is annealed at 600 ℃, antiferromagnetic element Cr has apparent segregation, while other elements do not segregate apparently, which promotes the increase of saturation magnetization (Ms). The films show high resistivity (110–120 μΩ⋅cm) and good mechanical properties, even after annealing at 800 °C, showing excellent thermal stability.

Magnetic, magnetodielectric, and magnetoimpedance correlations in co-substituted (Co, Ho) KBiFe2O5 at room temperature

The exotic physical properties of unique brownmillerite KBiFe2O5 (HC0) are enhanced by co-substituting rare-earth Holmium (Ho) and transition metal Cobalt (Co), ion and establishing their interaction. Dielectric, structural, magnetic, magnetodielectric (MD), and magnetoimpedance (MI) properties of co-substituted KBi1−xHoxFe2(1−y)CoyO5 [x = y = 0, 0.05, 0.1, & 0.15] are investigated. The solid-state reaction method is used to synthesize, and the Rietveld refined powder X-ray diffraction patterns confirm the monoclinic structure with the P2/c space group. The Raman shift decreases, but the lattice strain increases with increased co-doping and correlates with MD data. The room temperature (RT) remnant (MR) and saturation (MS) magnetization increase by ∼ 20 and ∼ 2 times, respectively, with co-doping. The magnetic anomaly near dielectric transition (∼ 500 °C for KBi0.95Ho0.05Fe1.9Co0.05O5) suggests the signature of MD coupling for the co-doped samples. The MD and magneto-loss (ML) strength of HC0 increase with co-doping from 0.35 % to 0.65 % and 0.65 % to 1.25 %, respectively. In addition, the MD coupling coefficient increases from 4 % to 11 %, with the increase in co-doping. The RT MI curve of KBi0.85Ho0.15Fe1.75Co0.15O5 (HC15) shows an enhanced symmetric hysteresis loop (butterfly-like) with a maximum strength of ∼ 0.6 %. The frequency-dependent MD of HC0 shows that the maximum MD% at a high frequency (> 50 kHz) is enhanced with the increase in co-doping, and the corresponding MD and ML strength of HC15 are − 1.2 % and − 0.4 %, respectively. The dielectric relaxation time for HC15 shows maximum non-linear variation with the magnetic field, suggesting an intrinsic contribution to MD coupling. The observed dielectric transition (TC) around 510 °C of HC0 decreases to 480 °C (for HC15) with the increase in the co-doping. Thus, enhanced MD coupling and magnetic field-controlled dielectric relaxation for co-doped HC0 make this material suitable for next-generation spintronic and storage device applications.

NiTiO3/MnFe2O4 ferrite composites: synthesis, optical, ferroelectric and magnetic properties

Abstract This work reported the successful synthesis of ilmenite-spinel (1 − x)NiTiO3-xMnFe2O4 (x = 0, 0.05 and 0.10) composites by a simple sol-gel method. Phase formation of composites was analyzed by the X-ray diffraction method. All the synthesized samples formed diphasic ilmenite-ferrite composites without any trace of impurity or intermediate phase. The optical properties of synthesized composites were characterized by diffuse reflectance UV–visible spectroscopy. MnFe2O4 phase modified the optical band gap of NiTiO3 material and shifted its optical bandgap value toward lower energy. Ferroelectric and magnetic hysteresis loops were investigated at room temperature. The hysteresis loops indicated the typical ferromagnetic and ferroelectric nature of all composites at room temperature. In P-E loops, the remanent polarization (Pr ) and saturation polarization (Ps ) showed a slight increase in the sample with 5% MnFe2O4 phase addition. However, the lossy P-E loop was observed in the sample with the addition of 10% MnFe2O4. The presence of ferrite MnFe2O4 phase in NiTiO3 material enhanced the magnetic properties of NiTiO3 at room temperature. The M-H loops of NiTiO3-MnFe2O4 composites presented a ferromagnetic behavior with a dramatic increase in saturation magnetization with an increase of ferrite phase addition.

Nanocrystal evolution during ultra-fast heating in an amorphous Fe85B15 alloy

During the crystallization of Fe-based metallic glasses the precipitation of the BCC-Fe nanocrystals smaller than the exchange length (30–40 nm) has been reported as an effective strategy for a reduced coercivity and an increased saturation magnetization. In binary Fe-B alloys it has been shown that nanocrystals well below the exchange length can be obtained by rapid heating above 100 K/s. In order to determine if the fast heating process can yield a further refinement in nanocrystal size, the influence of different heating rates (0.17–5000 K/s) on the crystallization behavior of an amorphous Fe85B15 alloy was investigated using Flash DSC and TEM. Above a critical heating rate (500 K/s), the number density and diameters of BCC-Fe nanocrystals become saturated due to diffusion-field impingement that enriches the amorphous matrix with B that leads to the precipitation of Fe3B nanocrystals that deteriorate the magnetic properties.

Effect of Sr-Doping on Structural and Magnetic Properties of La1−xSrxMnO3 Nanoparticles

Polycrystalline La[Formula: see text]SrxMnO3 ([Formula: see text]–0.4) lanthanum strontium manganese oxide (LSMO), nanoparticles exhibit interesting size-dependent structural and magnetic properties. LSMO nanoparticles have attracted considerable attention in recent years because of their tunable magnetic properties like intrinsic and extrinsic colossal magnetoresistance, single domain superparamagnetic structure with near room temperature Curie point ([Formula: see text]). They find interesting applications in catalysis, biomedicine and data storage. Properties of LSMO nanoparticles are strongly correlated to extent of Sr-doping at La-site, their particle size and the extent to which different crystallographic phases (rhombohedral/orthorhombic) appear. A major aim of this study is to understand the effect of Sr-doping on the structural and magnetic properties of LSMO nanoparticles synthesized via the sol–gel auto combustion route. Structural and magnetic properties were investigated by powder X-ray diffraction coupled with Rietveld refinement and vibrating sample magnetometer, respectively. Rietveld refinement of diffractograms revealed that irrespective of Sr-doping, LSMO nanoparticles were crystallized in rhombohedral ([Formula: see text]) and orthorhombic (Pbnm) mixed phases. The rhombohedral phase appears to be the dominant crystallographic phase. VSM study revealed that irrespective of Sr-doping LSMO nanoparticles exhibit soft ferromagnetic behavior. With the increase in Sr-doping, saturation magnetization ([Formula: see text]) of LSMO nanoparticles increases, while their Curie temperature remains constant at [Formula: see text][Formula: see text]K. To establish the correlation between structural and magnetic properties of LSMO nanoparticles, [Formula: see text]–[Formula: see text] curves were fitted with modified Langevin function. It was observed that with an increase in Sr-doping, magnetic domain size, polydispersity and saturation magnetization increase. This increase is attributed to the corresponding increase in the rhombohedral phase fraction of LSMO nanoparticles. Thus, through Sr-doping, the magnetic properties of LSMO nanoparticles can be tuned by controlling their crystallographic phase fractions.

The Preparation of High Saturation Magnetization and Low Coercivity Feco Soft Magnetic Thin Films via Controlling the Thickness and Deposition Temperature.

FeCo thin films with high saturation magnetization (4 πMs) can be applied in high-frequency electronic devices such as thin film inductors and microwave noise suppressors. However, due to its large magnetocrystalline anisotropy constant and magnetostrictive coefficient of FeCo, the coercivity (Hc) of FeCo films is generally high, which is detrimental to the soft magnetic properties. Meanwhile, the thickness and deposition temperature have significant effects on the coercivity and saturation magnetization of FeCo films. In this paper, FeCo thin films with different thicknesses were prepared by magnetron sputtering at different temperatures. The effects of thickness and deposition temperature on the microstructure and magnetic properties of FeCo thin films were systematically studied. When the film thickness increases from 50 nm to 800 nm, the coercivity would decrease from 309 Oe to 160 Oe. However, the saturation magnetization decreases from 22.1 kG to 15.3 kG. After that, we try to further increase the deposition temperature from room temperature (RT) to 475 °C. It is intriguing to find that the coercivity greatly decreased from 160 Oe to 3 Oe (decreased by 98%), and the saturation magnetization increased from 15.3 kG to 23.5 kG (increased by 53%) for the film with thickness of 800 nm. For the film with thickness of 50 nm, the coercivity also greatly decreased from 309 Oe to 10 Oe (decreased by 96%), but the saturation magnetization did not change significantly. It is contributed to the increase of deposition temperature, which will lead to the increase of grain size and the decrease of the number of grain boundaries. And the coercivity decreases as the number of grain boundaries decreases. Meanwhile, for the thicker films, when increasing the deposition temperature the thermal stress increases, which changes the appearance of (200) texture, and the saturation magnetization increases. Whereas, it has a negligible effect on the orientation of thin films with small thickness (50 nm). This indicates that high-temperature deposition is beneficial to the soft magnetic properties of FeCo thin films, particularly for the films with larger thickness. This FeCo thin film with high saturation magnetization and low coercivity could be an ideal candidate for high-frequency electronic devices.

Cation distribution in MFe2O4 (M = Ni, Co): X-ray diffraction, electron spectroscopy, Raman, and magnetization studies

We report the structural, vibrational, surface composition, and magnetic properties of as-prepared and annealed (600–1200 °C) MFe2O4 (M = Ni, Co) samples to investigate the cation distribution. Rietveld refinement of X-ray diffraction data indicated a spinel structure for all samples. Raman and X-ray photoelectron analyses suggest the presence of an inverse spinel structure in the samples. Furthermore, the mixed valence states (Fe2+, Fe3+, Ni2+/Co2+) of the cations and their occupancies over tetrahedral and octahedral sites have been evaluated. We have noticed a systematic increase in saturation magnetization (MS) (10.7–43.5 emu/g for NiFe2O4, 36.1–83 emu/g for CoFe2O4) with increasing annealing temperature up to 1000 °C, and then MS slightly decreased for the samples annealed at 1200 °C. Furthermore, the values of coercivity (HC) varied over the ranges 15–125 Oe for NiFe2O4 and 300–1644 Oe for CoFe2O4, suggesting that these materials are promising candidates for biomedical and high-frequency applications.

Room and low-temperature magnetic characterization of Cr doped CoFe2O4 nanostructures

The macroscopic magnetism in nanoparticulated systems is the consequence of numerous contributions, ranging from the spatial arrangement of nanoparticles to their intrinsic nanostructure. Understanding and unraveling these temptations is essential to scientifically and technologically introduce nanomaterials. In the present work, we investigate how the magnetic properties of Co ferrite can be significantly ameliorated by Cr substitution. At first, applied the co-precipitation strategy to synthesize stoichiometric Co ferrite nanoparticles followed by the Cr substitution to achieve CoCrxFe2-xO4 (0 ≤ x ≤ 1) nanoparticles. The phase and structural analysis by X-ray diffraction identified the formation of spinel structure with the Fd-3m space group. An increasing behaviour in X-ray density with Cr substitution in Co ferrite has been observed due to lattice contraction. Field-emission scanning electron microscopic images confirmed that the particle size ranged from 14 to 17 nm. Room temperature magnetic investigations showed that the magnetic coercivity of the synthesized nanoparticles increased up to 40% Cr substitution, followed by a monotonic decrease in the magnetic properties. Low-temperature magnetic properties were carried out for 40% Cr substituted Co ferrite. The increase in saturation magnetization with a reduction in temperature followed Bloch's law, and the trend of temperature-dependent coercivity was confirmed with Kneller's law.

Impact of Ga3+ Ions on the Structure, Magnetic, and Optical Features of Co-Ni Nanostructured Spinel Ferrite Microspheres.

Co-Ni ferrite is one of the crucial materials for the electronic industry. A partial substitution with a rare-earth metal brings about modification in crystal lattice and broadens knowledge in the discovery of new magnetic material. Current work reports a Ga3+ substitution in the Co-Ni ferrite with composition Co0.5Ni0.5Fe2−xGaxO4 (where x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0), herein referred to as spinel ferrite microspheres (CoNiGa-SFMCs). The samples were crystallized hydrothermally showing a hollow sphere morphology. The crystal phase, magnetic, morphology, and optical behaviour were examined using various microscopy and spectroscopic tools. While the XRD confirmed the phase of SFMCs, the crystallite size varied between 9 and 12 nm. The Tauc plot obtained from DRS (diffuse reflectance spectroscopy) shows the direct optical energy bandgap (Eg) of the products, with the pristine reading having the value of 1.41 eV Eg; the band gap increased almost linearly up to 1.62 eV along with rising the Ga3+ amount. The magnetic features, on the other hand, indicated the decrease in coercivity (Hc) as more Ga3+ is introduced. Moreover, there was a gradual increase in both saturation magnetization (Ms) and magnetic moment () with increasing amount of Ga3+ till x = 0.6 and then a progressive decline with increases in the x content; this was ascribed to the spin-glass-like behavior at low temperatures. It was detected that magnetic properties correlate well with crystallite/particle size, cation distribution, and anisotropy.

Microstructure evolution and magnetic shielding effect of permalloy deposition on molybdenum substrate by electron beam freeform fabrication

In view of the excellent soft magnetic properties, 1J85 permalloy was deposited on molybdenum substrate by electron beam freeform fabrication to achieve magnetic shielding effect for molybdenum substrate. The magnetization of molybdenum substrate was increased from 0.04 emu/g to 8.96 emu/g after depositing permalloy layer, corresponding to the decrease in coercivity from 169.44 Oe to 7.33 Oe. The saturation magnetization was increased with the increased heat input. The cellular grain boundaries were demonstrated to be element segregation instead of the conventional dislocation-walls. A reaction layer consisting of numerous Mo-Ni binary phases was located at the interface between permalloy deposition and molybdenum substrate, indicating the maximum microhardness value. The shear strength of the interface between permalloy deposition and Mo substrate was firstly increased and then decreased with the increased heat input. The residual stress in permalloy deposition corresponded to local misorientation and dislocation, which was detrimental to soft magnetic properties. The decrease in residual stress was the main reason for the increased saturation magnetization with the increased heat input. • Magnetic shielding effect of permalloy deposition on Mo substrate was prominent. • Magnetic and mechanical properties and reasons for their change are analyzed. • Influence of residual stress, local misorientation and dislocation on properties are analyzed. • Solidified model of reaction layer in deposition was built.

Synthesis and characterizations of Mg-Cu-Co-Dy ferrites and their composites with graphene nanoplatelets (GNP)

Nanocrystalline spinel ferrite Mg0.5Cu0.25Co0.25Fe1.97Dy0.03O4 (MCCD-ferrites) and their composites with graphene nanoplatelets (GNP =0.0%, 1.25% 2.5%, 3.75%, 5%) were prepared by sol-gel technique and sintered at 850 oC for 5 hours. Measurements in the areas of X-ray diffraction, electrical, optical, dielectric and magnetic properties were used to analyze the effects of the inclusion of graphene with ferrite nanoparticles. The crystallite size was determined in the range of 27.62 – 41.46 (nm). The optical bandgap was found in the range of 3.50 eV to 2.88 eV. The dielectric loss was measured between 8 Hz and 8 MHz at room temperature (RT). Magnetic characteristics of the materials are measured and calculated. The magnetic performances of MCCDF-GNP Composites nanoparticles are improved with an increase in saturation (Ms) magnetization. This material can be utilized for humidity sensors, antennae, and micro memory chips.

Structural and temperature-dependent magnetic characteristics of Ho doped CoFe2O4 nanostructures

The magnetism in low-dimensional materials is the consequence of several factors, including the type of crystal structure and spatial distribution of nanoparticles. Understanding and exploring these challenges are vital to introduce nanomaterials for industrial applications. The present study reveals the substitutional effect of Holmium on the magnetic properties of cobalt ferrite. The nanostructures are prepared by co-precipitation procedure for the stoichiometric growth of CoHoxFe2-xO4 (0 ≤ x ≤ 0.1); Δx = 0.025 ferrite compositions. The crystal structure and phase determination of all the samples identify a typical cubic structure (Fd-3m); however, a secondary phase, appearing at x = 0.1, originates due to the formation of HoFeO3. An increasing trend in lattice constant, X-ray density and hopping lengths with Ho doping in Co ferrite is observed in the synthesized nanoparticles. The structural analysis by high-resolution transmission electron microscopy confirms the crystal structure of spinel ferrite. The magnetic characteristics measured at room temperature depict that the coercivity, saturation magnetization, and magneton number increase due to the impact of Ho3+ substitution. The saturation magnetization of CoHo0.05Fe1.95O4 nanoparticles as a function of temperature satisfies Bloch's law, and the coercivity of the sample remained in good agreement with Kneller's law.

Effect of microwave processing on Mn doped ZnO diluted magnetic semiconductor characteristics

5 and 7.5 at% Mn doped ZnO samples were prepared by microwave treatment following thermal curing. The XRD phase analysis reveals the Mn may be present in the unreacted Mn3O4 form or bonded with wurtzite ZnO forming substitutional solid solution (Zn0.99Mn0.01O and Zn0.95Mn0.05O) or spinel (ZnMn2O4). The Fourier transform infra-red (FTIR) band shift to higher wavenumber for the microwave treated samples appearing at 538 and 619 cm−1 indicates formation of ZnMn2O4 spinel structure. Identification of tiny particles in the wall of ZnO lamellae and decrease in Zn2p binding energy signifies vigorous chemical changes taken place on microwave treatment. The structural evolution was depicted by 3d modelling. Quantitative estimation of Mn in the samples was performed by microwave plasma atomic emission spectroscopy (MPAES) and the result matches with the calculated value. Raman spectroscopy shows clear peaks of ZnO, Mn3O4 and MnO2 compounds for all the samples prepared. Whereas, shoulder peak of ZnMn2O4 is observed for 7.5 at% Mn doped microwave pre-treated sample. The optical absorption spectra show major peak near to 360 nm signifying bandgap of ZnO in the visible range. The cation substitution in the host lattice by dopant creates oxygen vacancy (VO) in excess, responsible for increasing bound magnetic polaron, which is clearly evidenced by the presence of broad PL peak near to 535 nm and 548 nm for microwave treated samples. The microwave treatment assists the incorporation of Mn into ZnO lattice as evidenced by reduction of photoluminescence (PL) peak intensity. The magnetic hysteresis loop (B-H curve) of the samples clearly shows increase in saturation magnetisation by ~16.1 and ~24.7 % on microwave treatment of 5 and 7.5 at% Mn doped ZnO respectively.

Biocompatible Tb doped Fe3O4 nanoparticles with enhanced heating efficiency for magnetic hyperthermia application

Magnetic hyperthermia has a specific limitation in treating localized and relatively accessible malignant tumors regardless of its promising therapeutic regime. In this present work, Tb doped Fe3O4 magnetic nanoparticles (MNPs) prepared via coprecipitation root and confirmed the structural conformation and phase purity by XRD, FTIR, TEM, and SEM analysis. TGA analysis was carried out for thermal stabilization and to verify the formation of a stable phase. The occupancy of Tb ions at the octahedral sites and cationic distribution can be calculated from Rietveld refinement analysis. The relaxation mechanism, dipolar- dipolar interactions among the particles, and randomly directed magnetic anisotropy axes were investigated by ESR spectroscopy. The magnetic results enumerate that increasing Tb doping concentration leads to increased saturation magnetization and decreased coercivity and retentivity. The self-heating properties of the doped nanoparticles were characterized by measuring specific absorption rate (SAR). The improved saturation magnetization and enriched SAR value enable the doped MNPs for magnetic hyperthermia application with excellent efficacy.