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This paper presents a theoretical and experimental analysis of nonlinear magnetic transmission lines and demonstrates the phenomenon and capability of a simultaneous rise and fall time compression. A theoretical approach is formulated in which a new version of the modified Korteweg–de Vries equation is developed utilizing the Gardner–Morikawa transformation, continuum limit approximation, Toda-lattice approximation, and Mei theory of Maxwellian circuits. The proposed theoretical foundation work is validated through experimental demonstration. The pulse generation in a nonlinear magnetic transmission line is then studied in detail, and the output pulse characteristics are explored under different magnetic field strengths and arbitrary magnetization directions. In particular, output waveforms are analyzed in terms of pulse amplitude, full width half maximum, detailed ringing level, and figure of merit. Magnetic losses that arise in the ferrite material are modeled. It is shown that these losses are responsible for originating dissipative effects, which in turn deteriorate pulse shaping and increase ringing level. The localized disturbance within ferrimagnetic materials is also studied, and its impact on the output waveforms is also discussed. This study can potentially open up a new and fruitful entry to explore magnetic materials and their impacts in the field of ultrafast electronics in parallel with nonlinear electrical transmission lines. [ABSTRACT FROM AUTHOR]

Spin-crossover (SC) compounds are fascinating materials that exhibit colorful phase transitions induced by temperature, pressure, photoirradiation, etc. From the microscopic point of view, the electronic (spin) state of a molecule changes between the low-spin (LS) and high-spin (HS) states by such stimuli, and a variation of the molecular size follows through the vibronic coupling between the electronic state and structure in the molecule. This causes an elastic distortion and then an elastic interaction. The elastic interaction is essential in cooperative properties of SC phenomena. In this paper, we present a tutorial study on elastic interaction models for SC phenomena, which are the recent trend of modeling of SC compounds. We focus on multistep transitions, which are a topic of SC phenomena. We analyze the phase diagrams including the metastable phases for several SC systems, in which antiferromagnetic-like and ferrimagnetic-like phases are associated in addition to the LS and HS phases. Making use of the phase diagrams, we show various patterns of thermally induced SC transition with steps. We also investigate SC transitions with steps in a core-shell SC nanocomposite composed of two different SC compounds. We focus on two cases: the core has a lower transition temperature than the shell, and the core has a higher transition temperature. We show characteristic features of difference in the two systems. [ABSTRACT FROM AUTHOR]

A ferrimagnet (FiM) has small domains consisting of oppositely polarized and unequal magnetic moments. Oppositely polarized magnetic moments have strong exchange coupling between them resulting in robust torque in FiM called bulk torque. Due to the strong bulk torque, magnetic moments in FiM do not precess around the switching axis for a long time unlike ferromagnets (FMs) leading to faster switching speed compared to FM. In this paper, we propose and model the switching of FiM (CoTb) with spin current injection from heavy metal with strong spin Hall effect (SHE) such as Pt. We carry out ab initio calculation of the Dzyaloshinskii-Moriya interaction (DMI) at the FiM(CoTb)/heavy metal(Pt) interface using spin polarized relativistic Korringa-Kohn-Rostoker (KKR) Green's function method. We compute the exchange coupling among the magnetic moments inside the CoTb layer and model how the spin-orbit torque (SOT) along with the bulk torque can efficiently switch the FiM. Then, we consider a ferrimagnet based magnetic tunnel junction (FMTJ) with SHE metal. We perform a comprehensive simulation and performance analysis of FiM(CoTb)/MgO/CoFeB and FiM(CoTb)/MgO/FiM(CoTb) FMTJs with Pt underlayer. Using non-equilibrium Green's function (NEGF) formalism, we calculate the tunneling magnetoresistance (TMR) of the proposed FMTJs at room temperature. Furthermore, the importance of thickness in CoTb magnetization dynamics is shown using our FiM magnetization simulation framework. We analyze and show that the CoTb based FMTJ has large switching energy barrier to ensure thermal stability. Finally, we show the performance comparison (TMR, write performance and power consumption) between our proposed FMTJs and FM based MTJ and our simulation exhibits that for picosecond range switching speed, FMTJ is ∼ 25 times more energy efficient than FM based MTJ. [ABSTRACT FROM AUTHOR]

Minimizing magnetic field emissions to surroundings are one of the most challenging design criteria for wireless power transfer to vehicles. In this paper, concept of division of the emissions into three zones (primary, secondary, and combined zone) in the vertical direction is introduced. For geometries without ferrite, these zones can be defined only on basis of distance from coils. The simulation results indicate that magnetic field profile in the surroundings is influenced for ferrite based geometries and the three zones tend to overlap. This overlapping is studied via Comsol simulations for vertical separation between the coils in range of 100-180mm. It is observed that lower vertical separation results in higher overlapping of the zones and the coils behave as they are effectively placed close to center of air gap. The analysis in this work provides a better understanding of the space profile of magnetic field emissions (with and without ferrite) for wireless power transfer to vehicles. [ABSTRACT FROM AUTHOR]

This paper gives a quantitative comparison of magnetic couplers for electric vehicle (EV) wireless charging applications. Circular pad with ferrite spokes and coreless rectangular coils are specially selected for analysis. The dynamic flux density between couplers under high misalignment is studied by calculating the uncompensated power of the pick-up coupler. By using finite element analysis, the performance of each type of coupler is evaluated, and its adaptation to on-road EV charging are compared according to the flux distribution and effective charging area. [ABSTRACT FROM AUTHOR]

We improve thermal tolerance of a Co/Pt based synthetic ferrimagnetic (SyF) reference layer in a CoFeB/MgO-based perpendicular anisotropy magnetic tunnel junction by employing a surface modification treatment (SMT) using Ar plasma on a Pt buffer layer underneath the SyF layer. A higher perpendicular anisotropy and more robustness against annealing for the SyF reference layer is observed by the employment of SMT. From the cross-sectional scanning transmission electron microscope of the magnetic tunnel junction and atomic force microscopy on the Pt buffer layer, SMT has no significant effect on the surface roughness of the Pt buffer layer. On the other hand, X-ray diffraction analysis reveals that SMT increases the lattice spacing of the Pt buffer layer and shrinks that of the Co/Pt multilayer, which are maintained after annealing at 400 °C. Those structural changes could lead to the improvement of perpendicular anisotropy and thermal tolerance against annealing. A high-resolution Rutherford backscattering analysis reveals that Ar ions used for SMT penetrate to the Pt buffer layer, resulting in variation of the lattice spacing for the Pt buffer layer and Co/Pt multilayer. In addition, suppression of Fe diffusion from the CoFeB reference layer to the bottom Co/Pt multilayer is observed by using energy dispersive X-ray spectrometry, which also contributes to the higher thermal tolerance against annealing. The present observation reveals that the employment of SMT enables one to obtain both high perpendicular magnetic anisotropy and high robustness against annealing through crystallographic change of the Co/Pt multilayer and suppression of Fe diffusion from CoFeB layer into the Co/Pt multilayer. [ABSTRACT FROM AUTHOR]

It is established that 2D magnetic materials are the ideal platform for building up modern-day electronic and spintronic devices. The popular ways to achieve 2D magnetic materials are mechanical exfoliation and chemical vapor deposition. However, the direct chemical synthesis route of such magnetic 2D materials on a large scale is relatively unexplored. This article reports an easy and cost-effective facile chemical synthesis with a proper capping agent and magnetic study of free-standing 2D Cr2S3 nanosheets and Cr2S3 nanoparticles within the temperature range of 2–300 K under the magnetic field of up to 5 T. Although few magnetic results on 2D Cr2S3 are available in the literature, there is enough scope to work for an in-depth understanding of the magnetic aspects of this 2D material. Here, ferrimagnetic ordering with a sufficiently high coercivity of up to 0.139 T at 2 K along with a tendency to the saturation in magnetization down to a certain temperature limit is observed. Contrary to the strong antiferromagnetic coupling with a Néel temperature, as observed by previous researchers, is also observed for this chemically synthesized 2D Cr2S3 nanosheets. A transition temperature of 117 K is observed for the Cr2S3 nanosheets, whereas for Cr2S3 nanoparticles, a transition temperature of 101.7 K is observed with negligible coercivity. This facile synthesis technique may be applied to achieve other non-van der Waals type 2D magnetic materials. These kinds of non-van der Waals type 2D magnets will be useful to modern-day spintronic devices. [ABSTRACT FROM AUTHOR]

Fully compensated ferrimagnetic half metals have attracted great attention in spintronics. Unlike many previous calculations based on hypothetical ordered alloys, here we look for existing solid solution series taking as an example Co1−xCrxS2. Calculations find that a low-spin state for Cr that matches early experiments and a fully compensated ferrimagnetic half metal with Curie temperature above room temperature is found at x ≈ 0.33. Our study demonstrates the method of combining two half metals with light and heavy 3d metals in a solid solution to achieve compensation, where atomic disorder does not destroy the desired properties. [ABSTRACT FROM AUTHOR]

There is a growing interest in BiFeO3-based alloys because of the possibility it offers for developing high-temperature high-performance piezoelectric materials and for their interesting multiferroic properties. Often such ceramics are synthesized with additives either to reduce/suppress leakage current that the system inherits from the parent compound BiFeO3 or to promote sintering via formation of the liquid phase. We demonstrate here the propensity for stabilizing ferromagnetism in the ferroelectric solid solution BiFeO3–PbTiO3 (BF–PT) when synthesized with additive MnO2. Detailed investigation revealed that the ferromagnetic property of the ceramic is extrinsic and caused by the additive enabled precipitation of trace amount of the ferrimagnetic Pb-hexaferrite phase, not easily detected in conventional x-ray diffraction measurements. We also show that the ferromagnetic property is induced in Co-modified BF–PT. However, in this case, the additive stabilizes the CoFe2O4 spinel ferrite phase. While our findings offer a strategy to develop particulate magnetoelectric multiferroic composites using additive assisted precipitation of the ferrimagnetic phase(s) in BiFeO3-based ferroelectric alloys, it also helps in better understanding of the electromechanical response in BFO-based alloys. [ABSTRACT FROM AUTHOR]

We report different growth modes and corresponding magnetic properties of thin EuSe films grown by molecular beam epitaxy on BaF2, Pb1−xEuxSe, GaAs, and Bi2Se3 substrates. We show that EuSe grows predominantly in the (001) orientation on GaAs(111) and Bi2Se3, but along the (111) crystallographic direction on BaF2 (111) and Pb1−xEuxSe (111). High resolution transmission electron microscopy measurements reveal a sharp and highly crystalline interface for both (001) and (111) EuSe films. In agreement with previous studies, ordered magnetic phases include antiferromagnetic, ferrimagnetic, and ferromagnetic phases. In contrast to previous studies, we found a strong hysteresis of the antiferromagnetic–ferrimagnetic transition. The ability to grow epitaxial films of EuSe on Bi2Se3 and of Bi2Se3 on EuSe enables further investigation of interfacial exchange interactions between various phases of an insulating metamagnetic material and a topological insulator. [ABSTRACT FROM AUTHOR]

Using density functional theory, a detailed computational study is performed to explore the structural and electronic properties of a black phosphorene monolayer, bilayer, and trilayer under a uniaxial strain along the armchair (b axis) and zigzag (a axis) directions. In the case of a monolayer black phosphorene, it is found that strain along the armchair direction slightly affects the a lattice parameter and the puckering height (Δ). Along the zigzag direction, however, variation of the a lattice parameter is compensated by both the a and b lattice variations while the parameter Δ remains unaffected. In the case of bilayer and trilayer black phosphorene, a similar behavior is observed where the layer-spacing "d" acts as an additional degree of liberty for strain compensation. In terms of electronic properties, strain along the armchair and zigzag directions changes the nature of the Γ point in the bandgap from a direct to an indirect electronic transition as a function of the strain value. In the strain range from −14% to +6%, all black phosphorene structures behave similarly to classical semiconductors. However, the size and strain combined effect significantly affects the Fermi energy position. Around 0% strain, all black phosphorene structures are of p-type, while they switch to an n-type semiconductor in the range of strain values from +2% up to +14%. This p-type to n-type transition may have a major technological impact in fields where mono- and hetero-junctions are considered. [ABSTRACT FROM AUTHOR]

Spin Hall magnetoresistance (SMR) provides a unique opportunity for the signal readout of magnetic ordering, especially for magnetic insulators. However, the magnitude of SMR signals is quite small, generally lower than one in a thousand, which is a persistent challenge in the field of spintronics. Here, we investigate SMR at room temperature in α-Fe2O3/Pt and γ-Fe2O3/Pt bilayers as well as the α-Fe2O3/Pt/γ-Fe2O3 trilayer, where α-Fe2O3 and γ-Fe2O3 are antiferromagnetic and ferrimagnetic materials, respectively. In contrast to the positive SMR in the γ-Fe2O3/Pt bilayer, an unprecedentedly large negative SMR with the magnitude of ∼0.35% is observed in the α-Fe2O3/Pt bilayer due to the spin-flop. The α-Fe2O3/Pt/γ-Fe2O3 trilayer shows features of a combination of positive and negative SMR. A comparative study of SMR in the Fe2O3 family not only enriches spin physics, but also makes Fe2O3 a versatile candidate in spintronic devices. [ABSTRACT FROM AUTHOR]

We present a simple semiclassical model to sustain that in europium chalcogenides (EuX), Faraday rotation (FR) in the transparency gap is proportional to the magnetization of the sample, irrespective of the material's magnetic phase, temperature, or applied magnetic field. The model is validated by FR and magnetization measurements in EuSe in the temperature interval 1.7–300 K, covering all EuSe magnetic phases (paramagnetic, antiferromagnetic type I or type II, ferrimagnetic, and ferromagnetic). Furthermore, by combining the semiclassical model with the explicit electronic energy structure of EuX, the proportionality coefficient between magnetization and FR is shown to be dependent only on the wavelength and the bandgap. Due to its simplicity, the model has didactic value; moreover, it provides a working tool for converting FR into magnetization in EuX. The possible extension of the model to other intrinsic magnetic semiconductors is discussed. [ABSTRACT FROM AUTHOR]

A theoretical model based on the Landau-Lifshitz-Bloch equation is developed to study the effect of damping-like spin-orbit torque in ferrimagnets, which can capture many experimental findings. For example, the sample changes from Gd to FeCo dominate by increasing temperature, the damping-like spin-orbit torque has a peak at the magnetization compensation temperature, and angular-momentum compensation temperature increases as a function of Gd concentration. In contrast to the ferromagnet system, the switching trajectory in ferrimagnets is found to be precession free. The two sublattices are not always collinear, which produce a large exchange field affecting the magnetization dynamics. The study of material composition shows the existence of an oscillation region at intermediate current density, induced by the nondeterministic switching. Compared to the Landau-Lifshitz-Gilbert model, our developed model based on the Landau-Lifshitz-Bloch equation enables the systematic study of the spin-torque effect and the evaluation of ferrimagnet-based devices. [ABSTRACT FROM AUTHOR]

High-frequency coaxial waveguide measurements are used to evaluate composition- and frequency-dependent complex permittivities and permeabilities of polycrystalline ferroelectric and ferrimagnetic ceramics. Material dielectric and magnetic property measurements were performed on ferroelectric barium titanate (BaTiO3) and ferrimagnetic yttrium iron garnet (YIG), with the upper measurement frequency bound below gyromagnetic resonance of YIG. These polycrystalline materials were chosen because of their widespread use in voltage- and magnetic field-tunable devices. Wideband frequency material measurements were used to predict dielectric and magnetic properties of various two-phase composite media incorporating BaTiO3 and YIG. Two effective medium theories were used: an asymmetric, modified Maxwell-Garnett type and a symmetric Bruggeman model. The Bruggeman effective medium model is extended to include three-phases. The three-phase Bruggeman predictive model is employed when controlled porosity is introduced into the composite and when two component phases are combined with polytetrafluoroethylene. [ABSTRACT FROM AUTHOR]

CaCu3Fe4O12 exhibits a temperature-induced transition from a ferrimagnetic-insulating phase, in which Fe appears charge disproportionated, as Fe 3 + and Fe 5 + , to a paramagnetic-metallic phase at temperatures above 210 K, with Fe 4 + present. To describe it, we propose a microscopic effective model with two interpenetrating sublattices of Fe ( 4 − δ ) + + and Fe ( 4 + δ ) + + , respectively, δ being a measure of the Fe-charge disproportionation. We include all 3d-Fe orbitals: t 2 g localized orbitals, with spin 3/2 and magnetically coupled, plus two degenerate itinerant eg orbitals with local and nearest-neighbor (NN) electron correlations, and hopping between NN eg orbitals of the same symmetry. Allub and Alascio [J. Phys.: Condens. Matter 24(49), 495601 (2012)] previously proposed a model to describe the phase transition in LaCu3Fe4O12 from a paramagnetic-metal to an antiferromagnetic-insulator, induced by temperature or pressure, involving charge transfer between Fe and Cu ions, in contrast to Fe-charge disproportionation. With the model proposed for CaCu3Fe4O12, modified to account for this difference between the two compounds, the density of states of the itinerant Fe orbitals was obtained, using Green's function methods. The phase diagram of CaCu3Fe4O12 was calculated, including phases exhibiting Fe-charge disproportionation, where the two eg orbitals in each site are symmetrically occupied, as well as novel phases exhibiting local orbital selectivity/asymmetric occupation of eg orbitals. Both kinds of phases may exhibit paramagnetism and ferromagnetism. We determined the model parameters which best describe the phase transition observed in CaCu3Fe4O12 and found other phases in different parameter ranges, which might be relevant for other compounds of the ACu3Fe4O12 family, presenting Fe-charge disproportionation and intersite charge transfer Fe-Cu. [ABSTRACT FROM AUTHOR]

Peculiarities of low-temperature behavior of the magnetic properties of disordered spinel ferrites, prepared by means of dilution with the P2O5 amorphizing agent and by rapid quenching, were investigated. A sharp increase in the saturation magnetization σS, of ferrite compositions (1-x)MeFe2O4·xP2O5 (where Me is Ni, Fe, Mn, etc.), was observed at temperatures T < 80 K. It was established that the temperature dependences of σS and χ-1 (where v is the magnetic susceptibility) of the nickel ferrite composition (x = 0.6) have an extremum at T = 11 K. In this case, the effect of "memory" is observed for σS(T), which represents the dependence of σS (T = 4.2 K) on the magnitude of the magnetic field in which cooling was carried out. The asymptotic Curie temperature was determined by extrapolation of the linear part of the χ-1(T) dependence and found to be equal to -150 K. We present an analysis of the observed dependences from the viewpoint of a complex magnetic state, combining the features of the near antiferromagnetic and ferrimagnetic boundary-surface spin ordering. [ABSTRACT FROM AUTHOR]

We investigate the switching field distribution and the resulting bit error rate of exchange coupled ferri-/ferromagnetic bilayer island arrays by micromagnetic simulations. Using islands with varying microstructure and anisotropic properties, the intrinsic switching field distribution is computed. The dipolar contribution to the switching field distribution is obtained separately by using a model of a triangular patterned island array resembling 1:4Tb=in² bit patterned media. Both contributions are computed for different thicknesses of the soft exchange coupled ferrimagnet and also for ferromagnetic single phase FePt islands. A bit patterned media with a bilayer structure of FeGd(5 nm)/FePt(5 nm) shows a bit error rate of 10-4 with a write field of 1:16T. [ABSTRACT FROM AUTHOR]

Nanocomposites (NCs) comprising (1-x) BiFeO3 (BFO) and x SrFe12O19 (SRF) (x=0.1, 0.2, 0.3, and 0.4) have been prepared by a sol-gel route. Presence of pure phases of both BiFeO3 (BFO) and SrFe12O19 (SRF) in the NCs for x=0.3 and 0.4 has been confirmed by Rietveld analysis of XRD data though a minor impurity phase is observed in the case of x=0.1 and 0.2 NCs. Transmission electron micrographs of the NCs show that particles are mostly spherical with average size of 30 nm. M-H measurements at 300 and 10K indicate predominantly ferrimagnetic behavior of all the NCs with an increasing trend of saturation magnetization values with increasing content of SRF. Dielectric constant (εr) of the NCs at room temperature shows a dispersive behavior with frequency and attains a constant value at higher frequency. εr - T measurements reveal an increasing trend of dielectric constant of the NCs with increasing temperature and show an anomaly around the antiferromagnetic transition temperature of BFO, which indicates magnetoelectric coupling in the NCs. The variation of capacitance in the presence of magnetic field confirms the enhancement of magnetoelectric effect in the NCs. 57Fe Mössbauer spectroscopy results indicate the presence of only Fe3+ ions in usual crystallographic sites of BFO and SRF. [ABSTRACT FROM AUTHOR]

We report the co-existence of longitudinal ferrimagnetic behavior with Néel temperature TN~46.1 K and reentrant transverse spin-glass state at 44.05 K in Tin (Sn) doped cobalt-orthotitanate (Co2TiO4). The ferrimagnetic ordering is resulting from different magnetic moments of Co2+ on the A-sites (3.87 µB) and B-sites (5.069 µB). The magnetic compensation temperature (TCOMP) shifts from 31.74 K to 27.1 K when 40 at. % of "Sn4+" substitutes "Ti4+" at B-sites where the bulk-magnetization of two-sublattices balance each other. For T > TN, the dc-magnetic susceptibility (χdc = M/Hdc) fits well with the Néel's expression for the two-sublattice model with anti-ferromagnetic molecular field constants NBB~15.44, NAB~32.01, and NAA~20.88. The frequency dependence of ac-magnetic susceptibility χac data follows the Vogel-Fulcher law, and the power-law of critical slowing-down with "zν" = 6.01 suggests the existence of spin-clusters (where "z" and "ν" being dynamic critical-exponent and correlation length of critical-exponent, respectively). This system exhibits unusual hysteresis loops with large bipolar exchange-bias effect (HEB~13.6 kOe at 7 K) after zero-field cooling process from an un-magnetized state, and a dramatic collapse of remanence (MR) and coercive field (HC) across TCOMP. The possible origins of such anomalous characteristics were discussed. [ABSTRACT FROM AUTHOR]

The magnetization-induced second-harmonic generation (MSHG) effect was applied to study changes of magnetization distribution caused by H+2 ions implantation in magnetic garnet film of (111) symmetry. The evolution of the magnetization vector m in perpendicular magnetic field H was studied as a function of coherently rotated polarizers by an angle φ. The I2ω(H, φ) intensities exhibit completely different character as compared to the unimplanted film. The experimental results were explained in the frame of a phenomenological model of the MSHG effect, developed for the structure of 3m symmetry, composed of implanted and unimplanted sublayers. The theoretical approach allowed to determine the amplitudes and phases of nonlinear optical susceptibility tensor elements χ[2] as well as the m(H) vector components. In contrast to the linear magneto-optical Faraday effect, application of nonlinear MSHG method allows for simultaneous determination of all components of the magnetization vector in single experiment. It was found that contributions from the sublayers associated with mz components enter to the MSHG effect with opposite signs due to difference in phases of χ[2]. It is shown that m vector in the implanted sublayer undergoes spatial evolution vs H during the magnetization process, with a complex trajectory corresponding to the reorientation of the m(H) from sample plane to the normal direction. The developed methods can be useful in studies of other magnetic materials with intrinsic or artificially introduced inhomogeneities. [ABSTRACT FROM AUTHOR]

By using first-principles calculations, we investigated how to achieve a strong ferromagnetism in Cr-doped Si by controlling the atomic structure and Cr concentration as well as carrier densities. We found that the configuration in which the Cr atom occupies the tetrahedral interstitial site can exist stably and the Cr atom has a large magnetic moment. Using this doping configuration, room-temperature ferromagnetism can be achieved in both n-type and p-type Si by tuning Cr concentration and carrier densities. The results indicate that the carrier density plays a crucial role in realizing strong ferromagnetism in diluted magnetic semiconductors. [ABSTRACT FROM AUTHOR]

The spin-phonon coupling in magnetic materials is due to the modulation of the exchange integral by lattice vibrations. BaFe12O19 M-type hexaferrite, which is the most used magnetic material as permanent magnet, transforms into ferrimagnet at high temperatures, but no spin-phonon coupling was previously observed at this transition. In this letter, we investigated the temperature-dependent Raman spectra of polycrystalline BaFe12O19 M-type hexaferrite from room temperature up to 780K to probe spin-phonon coupling at the ferrimagnetic transition. An anomaly was observed in the position of the phonon attributed to the Fe(4)O6, Fe(5)O6, and Fe(1)O6 octahedra, evidencing the presence of a spin-phonon coupling in BaM in the ferrimagnetic transition at 720 K. The results also confirmed the spin-phonon coupling is different for each phonon even when they couple with the same spin configuration. [ABSTRACT FROM AUTHOR]

We present the structural and magnetic properties of Mn1-xFexV2O4 (x = 0.1, 0.2, and 0.3), and investigate the magnetocaloric effect in those compounds. The ferrimagnetic spin ordering is enhanced with the Fe doping at Mn site of MnV2O4, while the orbital ordering is suppressed. Large magnetic entropy changes up to 3.8 J/kg K as well as the relative cooling power up to 110 J/kg at the field change of 0-2 T for Mn1-xFexV2O4 are calculated from the isothermal magnetization measurements. The large orbital entropy change of MnV2O4 is suppressed by the Fe doping, while the spin entropy contribution arising from the strong spin-orbit coupling remains. Moreover, the doping of Fe broadens the temperature span of the large magnetic entropy change and increases the relative cooling power of MnV2O4 by 2.4 times. [ABSTRACT FROM AUTHOR]

The nature of magnetic ordering in the inverted spinel Co2SnO4 = [Co2+][Co2+Sn4+]O4 is investigated by measuring the temperature dependence of its magnetization (M) and ac-susceptibilities (χ′ and χ″) in different magnetic fields (H) using a superconducting quantum interference device magnetometer. The polycrystalline sample with a grain size of 3-5 μm was prepared by the solid-state route and characterized by x-ray diffraction and scanning electron microscopy. Above the ferrimagnetic Néel temperature TN = 41 K, χdc = M/H fits well with the Néel' expression for the two-sublattice model of ferrimagnetism. The ferrimagnetic ordering is suggested to result from different magnetic moments of Co2+ on the A sites (3.87 μB) and B sites (4.16 μB) and antiferromagnetic molecular field constants with magnitudes NAA = 13.6, NBB = 36.8, and NAB = 33.2. The temperature variations of χ′ and χ″ under various dc-bias fields suggest the existence of a spin-glass (SG) phase for T < TSG = 39.1 K in which only the transverse spin components are frozen below TSG. This co-existence of longitudinal ferrimagnetic order below TN = 41 K and transverse SG state below TSG = 39.1 K is suggested to result from the presence of non-magnetic Sn4+ ions on the B sites. [ABSTRACT FROM AUTHOR]

The purely phase-constant-nonreciprocal composite right-left handed metamaterial structure is proposed based on coplanar waveguides loaded with a ferrite layer. The structure exhibits considerably large nonreciprocity in phase constant which depends on the effective magnetization and whose magnitude can remain in leaky wave region of wavenumbers or can overcome a boundary to slow wave region. The nonreciprocity in amplitude of transmission coefficients, on the other hand, is effectively reduced by using a cavity-backed design to prevent undesired nonreciprocal radiation loss. [ABSTRACT FROM AUTHOR]

Structure and magnetic properties of the GdAl2-GdCo2 system including magnetocaloric effect have been investigated for various compositions. The as-cast GdCoxAl2-x alloys prepared by arc-melting crystallize in the dual-phase structure of cubic MgCu2-type and hexagonal MgZn2-type phases. All the as-cast dual-phase alloys exhibit only one magnetic phase transition near 77K even though two ferrimagnetic phases coexist. The magnetic transition was broadened by the continuous transitions of the component phases, which resulted in enhancement of relative cooling power at the expense of the magnetic entropy changes. [ABSTRACT FROM AUTHOR]

An optical scanning electromagnetic field probe system consisting of an optic crystal substrate and a galvano scanner has been developed for high speed, low-invasive measurement of electromagnetic near field distribution. We measured magnetic field distributions above a microstrip line using several magnetic garnet crystal substrates and the probe system. We observed that the frequency response in the gigahertz range improved when we applied a magnetic bias to the crystal. In addition, a magnetic field component in a particular direction could be detected by controlling the direction of the magnetic bias. [ABSTRACT FROM AUTHOR]

In this study, we investigated the magnetization response of the polycrystalline magnetic garnet film for stress. The calculation suggests that the balance of the magnetic anisotropic energy under magnetic field is an essential factor to modulate the magnetization by stress. We fabricated the magnetophotonic crystal based voltage driven type magneto-optic spatial light modulator, and measured the magneto-optic response for stress. The experimental results had a good agreement with our calculation. In our results, the magnitude and linearity of the modulation by stress was depending on static bias field, stress, and magnetostriction constant. The obtained results implied that the calculation could estimate the device performance by deciding material composition and prepare stress inside garnet. [ABSTRACT FROM AUTHOR]

The site preference and magnetic properties of Zn-Sn substituted strontium ferrite SrFe12-x(Sn0.5Zn0.5)xO19 particles with x=0-5 were studied using both 57Fe and 119Sn Mössbauer spectroscopies and magnetic measurements. The results show that the magnetization and magnetocrystalline anisotropy are closely related to the distributions of Zn-Sn ions on the five inequivalent crystal sites provided by the hexagonal structure of the ferrite. Mössbauer spectra show that the Zn-Sn ions preferentially occupy the 2b and 4f2 sites. The preference for these sites is responsible for the anomalous increase in the magnetization at low Zn-Sn substitutions. Based on microwave measurements of reflectivity, SrFe12-x(Sn0.5Zn0.5)xO19 is a good candidate for electromagnetic compatibility and other practical applications at high frequencies. [ABSTRACT FROM AUTHOR]