Saturation Magnetization Field Research Articles

AC Loss Reduction in HTS Coil Windings Coupled With an Iron Core

Rapid-cycling synchrotron (RCS) magnets based on a superferric design consist of high temperature superconducting (HTS) coil windings coupled with iron cores. However, the presence of iron cores significantly increases AC loss in HTS coil windings, making AC loss reduction a critical issue for applying HTS technology in RCSs. Enlarging the distance between iron cores and coil windings may reduce AC loss. In addition, magnetic materials with different saturation magnetic fields also may influence AC loss in HTS coil windings coupled with iron cores. To investigate the distance dependence, AC losses of 1DPC (double pancake coil)-, 2DPC-, 4DPC-, and 8DPC assemblies with various distances are simulated using the 3D <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</i> homogenization method with/without an iron core. Two magnetic materials with different saturation magnetic fields are chosen as the iron core to evaluate AC loss in HTS coil assemblies. The results show that the AC loss values in HTS coil assemblies coupled with the iron core decrease significantly with growing distance. For a given distance and current, when the iron core has a lower saturation field, the AC loss values of the 4DPC assembly are smaller than those with a higher saturation field.

An improved equivalent magnetic network model of IPM motor in electric vehicles for dynamic simulation of transient effects

The existing electric motor model for electric vehicles cannot address the simulation of transient conditions. Moreover, it is difficult to balance the computation time and simulation accuracy. To address these shortcomings, an improved internal permanent magnet motor model containing nonlinear magnetic field factors was proposed based on the equivalent magnetic circuit theory. The effects of the magnetic circuit saturation, cogging torque, and magnetic field harmonics on the electromagnetic torque could be reflected. Furthermore, the electromagnetic vibration and rotor eccentricity could be considered. To improve the computational efficiency of the equivalent magnetic network method, lumped parameter or mesh-based methods were used for flux paths with different complexities. Second, the single-layer mesh-based method with local variable permeability parameters improved the efficiency of the air-gap dynamic analysis and computational efficiency while simulating 2D flux paths. The radial and tangential electromagnetic forces were calculated using the Maxwell tensor method and the action on the rotor. The accuracy of the nonlinear magnetic field modeling was verified by finite element analysis and experimental. In addition, the motion modeling method and dynamic characteristics of the model were studied. A reference was provided for dynamic simulations of electric vehicles and other using permanent magnet motors.

Correlation between structural phase transition and physical properties of Co2+/Gd3+ co-substituted copper ferrite

The doping of the spinel ferrites with selective cations usually improves the properties of the parent ferrite. The effect of Co2+/Gd3+ co-substitution on the microstructure, optical, and magnetic properties of Cu1–xCoxFe2–xGdxO4 prepared by the citrate-nitrate auto-combustion synthesis was investigated. Characterization of the samples was performed with powder X-ray diffraction (XRD), Raman and Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy, X-ray energy-dispersive spectroscopy, UV-Vis spectroscopy, and a vibrating sample magnetometer. The results of XRD, Raman, and FTIR analysis show a gradual structural phase transition from a tetragonal (I41/amd) structure to a cubic (Fd3¯m) structure. The bandgap energy of the studied samples is in a range of 1.57–1.75 eV with a minimum in sample x = 0.06 and then increases. Magnetic investigations show that the presence of Co2+/Gd3+ cations in an octahedral site of the copper ferrite structure could increase saturation magnetization and coercive field from 567.9 Oe and 23.62 emu/g to 929.4 Oe and 28.27 emu/g, respectively.

Stability and Photothermal Properties of Fe3O4-H2O Magnetic Nanofluids.

Solar collectors are more efficient and commercial devices for collecting solar energy, compared to other solar energy utilizations. To improve the efficiency of solar collectors, it is important to prepare a liquid heat-collecting medium, which is stable and has high photothermal properties. Therefore, in this work, we develop a droplet-droplet mixing technique to prepare Fe3O4-H2O magnetic nanofluid. The results show that magnetic nanofluids prepared using the droplet-droplet mixing technique have more stable performance and a better encapsulation of dispersants than those prepared via traditional liquid-liquid mixing. Then, the thermal conductivity and photothermal properties of Fe3O4-H2O magnetic nanofluids are investigated experimentally and theoretically. The thermal conductivity and temperature of the magnetic nanofluid with Fe3O4 nanoparticles of a 1.0% volume fraction can reach the maximum value of 0.95 W/m∙K and 73.9 °C when the magnetic field strength is equal to the saturation magnetic field of 800 Gs. These findings provide insights into the potential applications of Fe3O4-H2O magnetic nanofluids in direct absorption solar collectors, heat exchangers, automobile radiators, etc.

Enhancing spin-transfer torque in magnetic tunnel junction devices: Exploring the influence of capping layer materials and thickness on device characteristics

We have developed and optimized two categories of spin-ransfer torque magnetic tunnel junctions (STT-MTJs) that exhibit a high tunnel magnetoresistance ratio, low critical current, high outputpower in the micro-watt range, and auto-oscillation behavior. These characteristics demonstrate the potential of STT-MTJs for low-power, high-speed, and reliable spintronic applications, including magnetic memory, logic, and signal processing. The only distinguishing factor between the two categories, denoted as A-MTJs and B-MTJs, is the composition of their free layers, two CoFeB/0.21 Ta/6 CoFeSiB for A-MTJs and two CoFeB/0.21 Ta/7 NiFe for B-MTJs. Our study reveals that B-MTJs exhibit lower critical currents for auto-oscillation than A-MTJs. We found that both stacks have comparable saturation magnetization and anisotropy field, suggesting that the difference in auto-oscillation behavior is due to the higher damping of A-MTJs compared to B-MTJs. To verify this hypothesis, we employed the all-optical time-resolved magneto-optical Kerr effect technique, which confirmed that STT-MTJs with lower damping exhibited auto-oscillation at lower critical current values. Additionally, our study aimed to optimize the STT-MTJ performance by investigating the impact of the capping layer on the device’s response to electronic and optical stimuli.

Unveiling new quantum phases in the Shastry-Sutherland compound SrCu2(BO3)2 up to the saturation magnetic field

Under magnetic fields, quantum magnets often undergo exotic phase transitions with various kinds of order. The discovery of a sequence of fractional magnetization plateaus in the Shastry-Sutherland compound SrCu2(BO3)2 has played a central role in the high-field research on quantum materials, but so far this system could only be probed up to half the saturation value of the magnetization. Here, we report the first experimental and theoretical investigation of this compound up to the saturation magnetic field of 140 T and beyond. Using ultrasound and magnetostriction techniques combined with extensive tensor-network calculations (iPEPS), several spin-supersolid phases are revealed between the 1/2 plateau and saturation (1/1 plateau). Quite remarkably, the sound velocity of the 1/2 plateau exhibits a drastic decrease of -50%, related to the tetragonal-to-orthorhombic instability of the checkerboard-type magnon crystal. The unveiled nature of this paradigmatic quantum system is a new milestone for exploring exotic quantum states of matter emerging in extreme conditions.

Sol-gel synthesis, structural, morphological, X-ray photoelectron spectroscopy and magnetic properties of Cd doped BaTiO3 nanostructures

The present study reports the new functionality of room temperature ferromagnetism (RTFM) in non-magnetic Cadmium (Cd) doped BaTiO3 nanostructures, contrary to pure diamagnetic BaTiO3. TEM images show that grain size reduces with Cd doping. XPS analysis indicates that cation vacancies induce RTFM in Cd doped BaTiO3. Magnetic study reveals that pure BaTiO3 exhibits diamagnetic like signature, while Cd doped BaTiO3 show ferromagnetic feature with saturation magnetization (Ms ∼ 9.70x10-3 emu/g), remanent magnetization (Mr ∼ 0.22x10-3 emu/g) and coercive field (Hc ∼ 42.54 Oe), respectively. The current investigation also indicates that the induced RTFM could meet the demand of developing spintronic applications.

Study of Synthetic Antiferromagnetic Nanostructures Based on CoFeB/Ru/CoFe

A study of the magnetic properties of synthetic antiferromagnetic nanostructures (SAF) has been carried out. In the SAF structure, two ferromagnetic layers separated by a nonmagnetic metal are coupled by the exchange RKKY interaction (Ruderman— Kittel—Kasuya—Yoshida), which has an oscillating character. The total magnetic moment of the SAF structure is minimal with an antiparallel configuration of the magnetization of the ferromagnetic layers, due to which the effect on the magnetic layers in the structure is reduced. The structures under study have a number of unique properties and are used in the elements of nonvolatile magnetoresistive memory, in magnetic field transducers, and in spin logic devices. The characteristics of the SAF of CoFeB/Ru/CoFe nanostructures with the Ru layer thickness corresponding to the second antiferromagnetic maximum are obtained. The magnetization reversal curves of SAF structures with Ru thickness of 2.1 nm, 2.3 nm and 2.5 nm have been studied. The optimal ratio of ferromagnetic layers was selected to reduce the magnetic moment of the SAF structure. A study of the effect of thermomagnetic treatment on the properties of the SAF nanostructure was carried out, which showed that there are no significant changes in the magnetization reversal, and the magnetic saturation field slightly increases. The curves of magnetization reversal of CoFeB/Ru/CoFe structures fixed by the antiferromagnetic layer are presented. In addition, magnetization reversal curves of spin-tunnel magnetoresistive nanostructures with an antiferromagnetic layer and a SAF structure are presented, and an analysis of the thermal stability of the structures with SAF is also carried out.

Enhanced magnetic anisotropy induced by praseodymium ferromagnetic order and anomalous transport properties in PrMn2Ge2 single crystals

Anisotropic magnetization and anomalous electrical transport properties of flux-grown $\mathrm{Pr}{\mathrm{Mn}}_{2}{\mathrm{Ge}}_{2}$ single crystals were investigated. The grown crystals exhibit strong magnetic anisotropy with easy magnetization along the $c$ axis. Linear magnetoresistance (MR) and a conventional anomalous Hall effect (AHE) are observed for $H\text{//}c$ and $I\text{//}b$ in contrast to a nonlinear positive MR and a large planar topological Hall effect (PTHE) observed for $H\text{//}a$ and $I\text{//}b$. The anisotropy of the magnetic and electrical transport properties is increased as temperature decreases because magnetic ordering of Pr atoms brings about an increase of the saturation magnetic field of nonlinear MR and the critical field for the maximum values of PTHE. A scaling analysis using the Tian-Ye-Jin model suggests that the AHE in this compound has a larger intrinsic contribution compared to the extrinsic contribution. The nonlinear positive MRs are attributed to the field-induced nontrivial spin textures. The PTHE is related to the real-space skyrmionic bubbles and the noncoplanar spin texture with nonzero spin chirality. These results demonstrate a magnetic field induced anisotropic magnetoresistance and Hall resistivity and its tunability by the ferromagnetic ordering of rare earth atoms in conical-ordered magnets.

Synthesis of multifunctional superparamagnetic mesoporous ZnMnFe2O4@Fe–CaSiO3 core-shell for medical applications

Herein, we report the synthesis of a mesoporous calcium silicate superparamagnetic nanoparticle as ZnMnFe2O4@Fe–CaSiO3 core-shell. This core-shell nanocomposite reveals excellent properties such as mesoporous nanocomposite, superparamagnetic at room temperature, low toxicity, large surface area, tunable pore size, and easy surface manipulation. The core nanocomposite (ZnMnFe2O4) is synthesized by the hydrothermal method, which shows a superparamagnetic behavior with an excellent saturation magnetization of 52.09 emu/g. The core-shell structure is prepared by a micellar-assisted sol-gel method, which uses a copolymer to create pores in the structure of CaSiO3. To improve the magnetic properties of the core-shell structure, different percent of Fe ions (0%, 5%, and 10%) are doped onto the calcium silicate structure; as for 10% Fe, i.e., ZnMnFe2O4@Fe10–CaSiO3, saturation magnetization and coercive magnetic field are 34.543 emu/g and 1Oe, respectively. In this configuration of nanocomposite, the pore volume and superparamagnetic property increase simultaneously. In addition, the core-shell mesoporous ZnMnFe2O4@Fe–CaSiO3 nanocomposite reveals comparable mesoporous channels (3.4–6 nm), while the amorphous structure of CaSiO3 has not been changed. These core-shell mesoporous superparamagnetic nanocomposites are evaluated in terms of drug loading and release using epirubicin (EPI) as a model drug. It is found that the increase of iron ions improves the capacity to stabilize the pH environment. Additionally, the mesoporous Fe–CaSiO3 nanostructures demonstrate a sustained drug release property that could be used in local drug delivery therapy. Therefore, these mesoporous superparamagnetic nanostructures would be a promising multifunctional platform for local drug delivery, magnetic resonance imaging, magnetic hyperthermia, and bone tissue regeneration.

Current-induced switching of thin film α−Fe2O3 devices imaged using a scanning single-spin microscope

Electrical switching of N\'eel order in an antiferromagnetic insulator is desirable as a basis for memory applications. Unlike electrically driven switching of ferromagnetic order via spin-orbit torques, electrical switching of antiferromagnetic order remains poorly understood. Here we investigate the low-field magnetic properties of 30-nm-thick, $c$-axis-oriented $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ Hall devices using a diamond nitrogen-vacancy center scanning microscope. Using the canted moment of $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ as a magnetic handle on its N\'eel vector, we apply a saturating in-plane magnetic field to create a known initial state before letting the state relax in low field for magnetic imaging. We repeat this procedure for different in-plane orientations of the initialization field. We find that the magnetic field images are characterized by stronger magnetic textures for fields along $[\overline{1}\overline{1}20]$ and $[11\overline{2}0]$, suggesting that despite the expected 3-fold magnetocrystalline anisotropy, our $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ thin films have an overall in-plane uniaxial anisotropy. We also study current-induced switching of the magnetic order in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$. We find that the fraction of the device that switches depends on the current pulse duration, amplitude, and direction relative to the initialization field.

Structural, Optical, and Magnetic Properties of Nitrogen-Doped Graphene Oxide Synthesized by Hydrothermal Method

The study examines how different nitrogen doping concentrations affect hydrothermally synthesized graphene oxide’s properties using various analytical techniques. Two analytical spectroscopic techniques were used to investigate UV–visible spectroscopy in dispersed samples, namely Bromo Phenol Blue (BPB) and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The results showed that the doped graphene samples absorb most light in the visible range between 476 nm and 568 nm in the presence of BPB, and the band gap values obtained using Tauc’s formalism ranged from 2.65 to 4.03 eV. In the presence of DDQ reagent, the formation of charge transfer complexes led to sharp absorption peaks in the ultraviolet region around 310 nm wavelength and a range of energy band gap values between 3.77 and 3.98 electron volts. Empirical Relations-Based Calculation of Refractive Index (n) for Nitrogen-Doped Graphene displayed Optical Absorption Potential in the Visible and UV ranges. Pyrrolic-N Bonding Dominance in Samples as Evident by X-ray Photoelectron Spectroscopy. The VSM results demonstrated that the sample with the highest percentage of Pyrrolic-N exhibited the highest saturation magnetization (0.23 emu gm−1) and coercive field (66.6 H Oe). The improved magnetic properties and optical band gap values observed in nitrogen-doped graphene oxide make them promising materials for use in magneto-optical devices.

Electric modulation of anisotropic magnetoresistance in Pt/HfO2–x /NiO y /Ni heterojunctions

Electric field control of magnetism through nanoionics has attracted tremendous attention owing to its high efficiency and low power consumption. In solid-state dielectrics, an electric field drives the redistribution of ions to create one-dimensional magnetic conductive nanostructures, enabling the realization of intriguing magnetoresistance (MR) effects. Here, we explored the electric-controlled nickel and oxygen ion migration in Pt/HfO2−x /NiO y /Ni heterojunctions for MR modulation. By adjusting the voltage polarity and amplitude, the magnetic conductive filaments with mixed nickel and oxygen vacancy are constructed. This results in the reduction of device resistance by ∼103 folds, and leads to an intriguing partial asymmetric MR effect. We show that the difference of the device resistance under positive and negative saturation magnetic fields exhibits good linear dependence on the magnetic field angle, which can be used for magnetic field direction detection. Our study suggests the potential of electrically controlled ion migration in creating novel magnetic nanostructures for sensor applications.

A high-efficiency C-band coaxial transit time oscillator with a dual-cavity extractor under low-magnetic fields

A high-efficiency C-band coaxial transit time oscillator with a dual-cavity extractor under low-magnetic fields is designed and studied through small-signal theory and particle-in-cell simulation. Small-signal theory analysis indicates that a dual-cavity extractor is superior to a single-cavity extractor in terms of the beam-coupling coefficient, the resonant frequency, and the external quality factor, which are good for high efficiency. Typical simulation results of the proposed device show that an output power of 1.73 GW and a frequency of 6.37 GHz can be obtained with a diode voltage of 455 kV and current of 9.75 kA. The corresponding power efficiency reaches 39%, and the guiding magnetic field is 0.8 T. Further simulation demonstrates that the power efficiency exceeds 34% in a rather large range of diode voltage from 385 kV to 470 kV and can reach higher than 35% with a low guiding magnetic field of 0.4 T. Then this coaxial transit time oscillator is compared with the typical relativistic backward wave oscillators from the magnetic field, efficiency and power saturation time.

Temperature annealing dependence of structural, magnetic, and antibacterial properties of silver substituted cobalt ferrite nanoparticles produced by coprecipitation route

In this study, silver-substituted cobalt ferrite (Ag0.02Co0.98Fe2O4) nanoparticles were successfully sensitized by the coprecipitation method. Annealing temperature treatment was used to modify the physical properties, i.e., 200 °C, 300 °C, 400 °C, and 500 °C. XRD analysis showed an increase in the annealing temperature, the crystallite size increased from 19.78 to 24.11 nm, and the grain size increased from 54.75 to 61.39 nm. The FTIR spectrum showed two prominent absorption bands around k ∼577 and k ∼381 cm−1, allowing metal oxide absorption in the tetrahedral and octahedral sites. There is a redistribution of cations which is more significant at the tetrahedral sites than at octahedral sites, toward a perfect spinel structure. An increased annealing temperature increased the saturation magnetization and coercive field from 31.80 to 50.60 emu g−1 and 651 to 1,077 Oe, respectively, attributable to an increase in the magnetocrystalline anisotropy constant. The evaluation of S. aureus and E. coli showed that Ag0.02Co0.98Fe2O4 indicated the zone of inhibition (ZOI) around the disks due to its antibacterial properties. The most significant on S.aureus and E.coli were 12.73 mm (mortality of 88%) and 12.43 mm (mortality of 80%), respectively, for Ag0.02Co0.98Fe2O4 annealed at 200 °C that have the minor grain size materials.

PANI-coated YIG/CFO hybrid composites as advanced electromagnetic wave absorber through X-band

Polyaniline (PANI)-coated Y3Fe5O12(YIG)/CoFe2O4(CFO) hybrid composites were synthesized via sol-gel and oxidative polymerization methods to achieve advanced microwave absorption properties. The structural, morphological, magnetic, and microwave absorption characteristics of the resulting samples were analyzed by performing X-ray diffraction (XRD), scanning electron microscopy (SEM), vibration sample magnetometer (VSM), and vector network analyzer (VNA). XRD results revealed that CFO and YIG have cubic crystal structures with Fd3m and Ia3d space symmetry, respectively, with an average crystallite size of 35.3 nm and 42.9 nm. The Ferro/ferrimagnetic signals were detected from the ferrite samples' room temperature magnetic hysteresis loops. The incorporation of PANI and YIG into the composites resulted in a decrease in their magnetic saturation (Ms) and coercive field (Hc) values. VNA measurements demonstrated that nearly all samples achieved 90% absorption (≤−10 dB) of incident electromagnetic waves throughout the X-band frequency range. The minimum reflection loss (RLmin) value reaches − 47.34 dB at 8.14 GHz, with an effective bandwidth of 4.00 GHz, covering the entire X-band and beyond. These impressive absorption characteristics suggest that the manufactured composites possess potential as viable candidates for defense applications conducted at X-band frequency.

Unusual spin–orbit torque switching in perpendicular synthetic antiferromagnets with strong interlayer exchange coupling

Synthetic antiferromagnet (SAF) is an outstanding system for controlling magnetic coupling via tuning the layer thickness and material composition. Here, we control the interlayer exchange coupling (IEC) in a perpendicularly magnetized SAF Pt/Co/Ir/CoFeB/MgO multilayer, which is tuned by varying the nonmagnetic layer Ir thickness and the magnetic layer Co thickness. And we study the spin–orbit torque (SOT) driven magnetization switching of the SAF. In the SAF with a weak IEC, the SOT-driven switching behavior is similar to that of a single ferromagnet system, which is dominated by the external magnetic field. In contrast, in the SAF with an ultra-strong IEC, the saturation magnetic field is large than 50 kOe, and the SOT-driven switching behavior is decided by the effective magnetic field. The effective field is correlated to the external magnetic field, the IEC field, magnetic moments of CoFeB and Co, and magnetic anisotropy. These results may advance the understanding of SOT switching of perpendicular SAFs and promote the applications of SAFs with low stray fields and lower power in spintronic devices.

Influence of substrate type and magnetic anisotropy on the spin Seebeck effect in ZnFe2O4 thin films

The longitudinal spin Seebeck effect (LSSE) has been investigated in ZnFe2O4 (ZFO) thin films on different substrates, such as Si (111), MgO (100), and SrTiO3 (100). The LSSE voltage signal exhibited a linear dependence on the temperature difference between both sides of the samples. The spin Seebeck coefficients were highly sensitive to the thermal conductivities of the magnetic layer and substrate, with values from 3 nV/k to 110 nV/K. Charge currents ({J}_{mathrm{c}}) and spin currents ({J}_{mathrm{s}}) densities were estimated. {J}_{mathrm{s}} values are similar for the samples deposited on MgO and STO. The saturation magnetic field for the LSSE signal was reached with a magnetic field lower than its bulk counterpart. These results were related to the lattice mismatch between the ZFO films and the substrate, the magnetic response, and the anisotropies present in the samples since a twofold in-plane anisotropy was observed for the sample deposited on Si, while the samples deposited on MgO and SrTiO3 showed a fourfold in-plane anisotropy. Moreover, the presence of a notable perpendicular magnetic anisotropy in the thin films may be a consequence of the lattice mismatch and at the same time, it can cause the saturation in the LSSE voltage hysteresis loop measured as a function of the external magnetic be reached with a low magnetic field.

Anelastic Effects in Fe-Ga and Fe-Ga-Based Alloys: A Review.

Fe-Ga alloys (GalFeNOLs) are the focus of attention due to their enhanced magneto-elastic properties, namely, magnetostriction in low saturation magnetic fields. In the last several years, special attention has been paid to the anelastic properties of these alloys. In this review, we collected and analyzed the frequency-, amplitude-, and temperature-dependent anelasticity in Fe-Ga and Fe-Ga-based alloys in the Hertz range of forced and free-decay vibrations. Special attention is paid to anelasticity caused by phase transitions: for this purpose, in situ neutron diffraction tests with the same heating or cooling rates were carried out in parallel with temperature dependencies measurements to control ctructure and phase transitions. The main part of this review is devoted to anelastic effects in binary Fe-Ga alloys, but we also consider ternary alloys of the systems Fe-Ga-Al and Fe-Ga-RE (RE-Rare Earth elements) to discuss similarities and differences between anelastic properties in Fe-Ga and Fe-Al alloys and effect of RE elements. We report and discuss several thermally activated effects, including Zener- and Snoek-type relaxation, several transient anelastic phenomena caused by phase transitions (D03 ↔ A2, D03 → L12, L12 ↔ D019, D019 ↔ B2, Fe13Ga9 → L12+Fe6Ga5 phases), and their influence on the above-mentioned thermally activated effects. We also report amplitude-dependent damping caused by dislocations and magnetic domain walls and try to understand the paradox between the Smith-Birchak model predicting higher damping capacity for materials with higher saturation magnetostriction and existing experimental results. The main attention in this review is paid to alloys with 17-20 and 25-30%Ga as the alloys with the best functional (magnetostriction) properties. Nevertheless, we provide information on a broader range of alloys from 6 to 45%Ga. Due to the limited space, we do not discuss other mechanical and physical properties in depth but focus on anelasticity. A short introduction to the theory of anelasticity precedes the main part of this review of anelastic effects in Fe-Ga and related alloys and unsolved issues are collected in summary.

The Modulated Magnetic Domain Structure in the La0.67Sr0.33MnO3 Ferromagnetic Films by Strain Engineering

Novel magnetic domain structures attract much attention due to their potential applications in the high performance of spintronic devices. Herein, the magnetic domains of La0.67Sr0.33MnO3 (LSMO) thin films, which epitaxially grown on (100)-, (110)-, and (111)-oriented (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) substrates, are systematically investigated. The (100)- and (110)-LSMO films show a stripe domain pattern. After in-plane magnetic field saturation, the direction of the stripe domains in (100)-LSMO no longer rotates with the change of magnetic field, while the stripe domains in (110)-LSMO rotate continuously. The (111)-LSMO films produce randomly distributed bubble-like magnetic domains, which gradually connect into strips with the increase of the external magnetic field, and the stability of the magnetic domain in (111)-LSMO is better than the ones in (100)- and (110)-LSMO under a magnetic field. In addition, it is found that with the increase of thickness, the random domains in (111)-LSMO films are gradually transformed into mazy domains. These phenomena can be understood by the regulable strain anisotropy and the magnetic anisotropy. Herein, an effective way is suggested to modify the magnetization anisotropy and magnetic domain because spin polarization depends strongly on the crystal surface orientation as well as epitaxial strain.