Showing papers on "Saturation (magnetic) published in 2005"
TL;DR: An overview of the magnetic properties of single-component and multiple-segment magnetic nanowires is presented, and examples of the influence of particle diameter, aspect ratio, and composition on many of their magnetic properties are provided.
Abstract: Magnetic nanorods or nanowires exhibit degrees of freedom associated with their inherent shape anisotropy and the ability to incorporate different components along their length. The introduction of multiple segments along the length of a nanowire can lead to further degrees of freedom associated with the shape of each segment and the coupling between layers. In this paper, we present an overview of the magnetic properties of single-component and multiple-segment magnetic nanowires, and we provide examples of the influence of particle diameter, aspect ratio, and composition on many of their magnetic properties: the orientation of their magnetic easy axis, their Curie temperature, coercivity, saturation field, saturation magnetization, and remanent magnetization.
356 citations
TL;DR: In this article, a nonlinear and coupled model is proposed to describe the constitutive relations for a Terfenol-D rod subjected to an axial pre-stress and then located in a axial magnetic field.
Abstract: To overcome some deficiencies in previous constitutive models of giant magnetostrictive materials, a nonlinear and coupled model is suggested to describe the constitutive relations for a Terfenol-D rod subjected to an axial pre-stress and then located in an axial magnetic field. The numerical simulation by the model proposed in this paper shows predicted magnetostrictive strain curves for various compressive pre-stresses in good agreement with the experimental data not only in the region of low and moderate magnetic field but also in the region of high field. In comparison with the previous models, the proposed model can more effectively describe the effect of the pre-stress on the maximum magnetostrictive strain. Moreover, the effect of the stress and the magnetic field on the Young’s modulus of the materials, i.e., the ΔE effect, can also be predicted. In the proposed model, there are only five material parameters. They are the saturation magnetization Ms, the saturation magnetostrictive strain λs, the intrinsic (or saturation) Young’s modulus Es and the initial Young’s modulus E0 as well as the linear magnetic susceptibility χm. Since these parameters are easily measured in experiments, the proposed model is convenient to be used in engineering applications.
216 citations
TL;DR: Recent progress made in electroplating alloys with high saturation magnetic flux density for use in writing heads is reviewed, with particular emphasis on the work done at IBM since the review paper on the subject was published in this journal in 1998.
Abstract: The continuous and rapid increase of areal density in magnetic data storage systems required a continuous increase of the coercivity of the storage media. In order to be able to record on these ever-higher-coercivity media, new soft magnetic materials for pole tips with increased magnetic moment had to be developed. Significant progress has been made during the last few years in electroplating alloys with high saturation magnetic flux density for use in writing heads. We review recent progress made in this area, with particular emphasis on the work done at IBM since the review paper on the subject was published in this journal in 1998 by Andricacos and Robertson. Reviewed here are the high-moment alloys of NiFe, particularly in the very high iron range [an extension of permalloy (Ni80Fe20) and Ni45Fe55]; very-high-cobalt CoFeCu alloys; ternary CoNiFe; and binary iron-rich CoFe alloys. With the latter binary alloy films, we have demonstrated that it is possible to reach by electroplating the saturation flux density limit of 2.4-2.5 T reported for cast alloys. Since the electroplating of good-magnetic-quality iron-rich CoFe alloys posed a considerable challenge, the behavior of the CoFe plating system was studied in detail, using in situ surface pH measurements and a rotating-cylinder Hull cell.
147 citations
TL;DR: In this article, the magnetoresistance of polycrystalline Co-films was studied in fields up to $120\phantom{\rule{0.3em}{0ex}}\mathrm{kOe}$, aligned along three principal directions with respect to the current: Longitudinal, transverse, and polar (out-of-plane).
Abstract: The magnetoresistance (MR) of $10--200\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ thin polycrystalline Co-films, deposited on glass and insulating Si(100), is studied in fields up to $120\phantom{\rule{0.3em}{0ex}}\mathrm{kOe}$, aligned along the three principal directions with respect to the current: Longitudinal, transverse (in-plane), and polar (out-of-plane). At technical saturation, the anisotropic MR (AMR) in polar fields turns out to be up to twice as large as in transverse fields, which resembles the yet unexplained geometrical size-effect (GSE), previously reported for Ni- and Permalloy films. Upon increasing temperature, the polar and transverse AMR's are reduced by phonon-mediated sd-scattering, but their ratio, i.e., the GSE remains unchanged. Basing on Potters's theory [Phys. Rev. B 10, 4626 (1974)], we associate the GSE with an anisotropic effect of the spin-orbit interaction on the sd-scattering of the minority spins due to a film texture. Below magnetic saturation, the magnitudes and signs of all three MR's depend significantly on the domain structures depicted by magnetic force microscopy. Based on hysteresis loops and taking into account the GSE within an effective medium approach, the three MR's are explained by the different magnetization processes in the domain states. These reveal the importance of in-plane uniaxial anisotropy and out-of-plane texture for the thinnest and thickest films, respectively.
128 citations
TL;DR: Simulations show that as the field decreases from saturation, the rings switch from a "bamboo" to a novel "twisted bamboo" state at a certain critical field, and predict a corresponding dip in the dependence of the spin wave frequency on the magnetic field.
Abstract: The spin dynamics of high-aspect-ratio nickel nanorings in a longitudinal magnetic field have been investigated by Brillouin spectroscopy and the results are compared with a macroscopic theory and three-dimensional micromagnetic simulations. Good agreement is found between the measured and calculated magnetic field dependence of the spin wave frequency. Simulations show that as the field decreases from saturation, the rings switch from a ``bamboo'' to a novel ``twisted bamboo'' state at a certain critical field, and predict a corresponding dip in the dependence of the spin wave frequency on the magnetic field.
126 citations
01 Jan 2005
TL;DR: In this paper, the magnetic properties of FINEMET-type nanocrystalline alloys and isolated ferromagnetic AgCo nanoparticles are investigated both experimentally and numerically.
Abstract: The magnetic properties of FINEMET-type nanocrystalline alloys and isolated ferromagnetic AgCo nanoparticles are investigated both experimentally and numerically. Theoretical models of spins that simulate ideal nanocrystalline alloys and isolated nanoparticles are considered while their magnetic properties are derived from Monte Carlo simulation of low-temperature spin ordering. Interesting features such as magnetic polarization of the matrix due to penetrating fields arising from nanograins and the role played by the crystalline fraction in the overall magnetic behaviour, in the case of nanocrystalline alloys are investigated. For isolated nanoparticles it is shown that the competition between surface and bulk anisotropy gives rise to surface spin disorder that, together with finite-size effects, is responsible for the experimentally observed lack of saturation of the magnetization in high applied fields. These simulation results are confirmed by experimental data obtained on FINEMET nanocrystalline alloys and isolated ferromagnetic AgCo colloidal nanoparticles.
118 citations
01 Jan 2005
TL;DR: In this paper, it was shown that the saturation magnetization and coercivity of the implanted single-phase films were both strong functions of the initial anneal temperature, suggesting that carrier concentration alone alone cannot account for the magnetic properties of ZnO:Mn and factors such as crystalline quality and residual defects play a role.
Abstract: ZnO is a very promising material for spintronics applications, with many groups reporting room temperature ferromagnetism in films doped with transition metals during growth or by ion implantation. In films doped with Mn during PLD, we find an inverse correlation between magnetization and electron density as controlled by Sn doping. The saturation magnetization and coercivity of the implanted single-phase films were both strong functions of the initial anneal temperature, suggesting that carrier concentration alone cannot account for the magnetic properties of ZnO:Mn and factors such as crystalline quality and residual defects play a role. Plausible mechanisms for the ferromagnetism include the bound magnetic polaron model or exchange is mediated by carriers in a spin-spilt impurity band derived from extended donor orbitals. We will also review progress in ZnO nanowires. The large surface area of nanorods makes them attractive for gas and chemical sensing, and the ability to control their nucleation sites makes them candidates for micro-lasers or memory arrays. Single ZnO nanowire depletion-mode metal-oxide semiconductor field effect transistors exhibit good saturation behavior, threshold voltage of∼-3V and a maximum transconductance of 0.3 mS/mm.Under UV illumination, the drain-source current increased by approximately a factor of 5 and the maximum transconductance was ∼ 5 mS/mm. The channel mobility is estimated to be ∼3 cm 2 /V.s, comparable to that for thin film ZnO enhancement mode MOSFETs and the on/off ratio was ∼25 in the dark and -125 under UV illumination. Pt Schottky diodes exhibit excellent ideality factors of 1.1 at 25 °C, very low reverse currents and a strong photoresponse, with only a minor component with long decay times thought to originate from surface states. In the temperature range from 25-150 C, the resistivity of nanorods treated in H 2 at 400 C prior to measurement showed an activation energy of 0.089 eV and was insensitive to the ambient used. By contrast, the conductivity of nanorods not treated in H 2 was sensitive to trace concentrations of gases in the measurement ambient even at room temperature, demonstrating their potential as gas sensors.
111 citations
TL;DR: In this paper, magnetic fine particles of cobalt ferrite (CoFe2O4) have been synthesized using complexometric method in which ethylene diamine tetra acetic acid C10H16N2O8 (EDTA) acts as a complexing agent.
110 citations
TL;DR: The saturation mechanism of the Weibel instability is investigated theoretically by considering the evolution of currents in numerous cylindrical beams that are generated in the initial stage of the instability.
Abstract: The saturation mechanism of the Weibel instability is investigated theoretically by considering the evolution of currents in numerous cylindrical beams that are generated in the initial stage of the instability. Based on a physical model of the beams, it is shown that the magnetic field strength attains a maximum value when the currents in the beams evolve into the Alfven current and that there exist two saturation regimes. The theoretical prediction of the magnetic field strength at saturation is in good agreement with the results of two-dimensional particle-in-cell simulations for a wide range of initial anisotropy.
109 citations
TL;DR: In this paper, a nonequilibrium rf magnetron cosputtering of ZnO and Cr metal on a plane Al2O3 was performed to find ferromagnetic ordering with a room-temperature saturation moment of 1.4μB per Cr ion at a doping concentration of ∼9.5 at.
Abstract: Through nonequilibrium rf magnetron cosputtering of ZnO and Cr metal on a-plane Al2O3 we find ferromagnetic ordering with a room-temperature saturation moment of 1.4μB per Cr ion at a doping concentration of ∼9.5 at. % after UHV postanneal. No secondary phases are detected in the films via x-ray diffraction (XRD). Increased Cr doping causes disorder within the films resulting in decreased overall, and per Cr, moment. The Curie temperature exceeds 365 K, the maximum temperature reached in our experiment. All films are dielectric with a resistivity higher than 106Ωcm at room temperature. The lack of carriers indicates that the ferromagnetic mechanism is not carrier mediated.
108 citations
TL;DR: The structural, magneto-optical, optical, and magnetic properties of BaTi1−xFexO3 films grown by pulsed laser deposition onto MgO (100) have been investigated for Fe content, x=0.15, 0.3, and 0.5 at a 1.55-μm wavelength, with corresponding saturation magnetizations of 11.3emu∕cm3 and 18.9dB∕mm.
Abstract: The structural, magneto-optical, optical, and magnetic properties of BaTi1−xFexO3 films grown by pulsed laser deposition onto MgO (100) have been investigated for Fe content, x=0.15, 0.2, 0.3, and 0.5. Saturation Faraday rotation varies from 0.033deg∕μm for x=0.2 to 0.109deg∕μm for x=0.5 at a 1.55-μm wavelength, with corresponding saturation magnetizations of 11.3emu∕cm3 and 18.3emu∕cm3. The optical absorption drops with a reduction in iron content and the BaTi0.85Fe0.15O3 sample has an optical absorption of 1.9dB∕mm. The magneto-optic figure of merit, which is the ratio of Faraday rotation to absorption, peaks at x=0.2 among the samples considered. The magnetic properties are interpreted in terms of the electronic structure of Fe4+ ions, and their exchange coupling with Fe3+ ions associated with oxygen vacancies.
TL;DR: In this article, a magnetorelaxometry system based on a differential fluxgate arrangement is presented, where the use of two fluxgate magnetometers increases the relaxation signal from the sample by a factor of 2 and the signal-to-noise ratio by 2.
Abstract: A magnetorelaxometry system based on a differential fluxgate arrangement is presented. Compared to the single fluxgate setup, the use of two fluxgate magnetometers increases the relaxation signal from the sample by a factor of 2, the signal-to-noise ratio by a factor 2, and allows one to perform magnetorelaxation measurements without any magnetic shielding. For a sample with superparamagnetic Fe3O4 nanoparticles and a volume of 150μl, 100 nmol Fe could be detected, limited by the intrinsic noise of the fluxgate sensors.
TL;DR: In this paper, a new technique for electrodeposition of CoNiMnP hard magnetic thin films is developed to provide thin films with low residual stress and magnetic properties useful for MEMS applications.
TL;DR: A reinvestigation of nearly stoichiometric RTiO3 samples showed that the transition from ferromagnetic to antiferromagnetic Ti-O-Ti interactions with increasing R3+-ion radius occurs at r3+≈111 ǫ where orthorhombic (Pbnm) RMO3 perovskites universally change structure from a cooperative rotation of undistorted to distorted MO6/2 octahedra about the orthogonal b-axis as discussed by the authors.
Abstract: A reinvestigation of nearly stoichiometric RTiO3 samples shows that (1) the transition from ferromagnetic to antiferromagnetic Ti–O–Ti interactions with increasing R3+-ion radius r3+ occurs at r3+≈111 A where orthorhombic (Pbnm) RMO3 perovskites universally change structure from a cooperative rotation of undistorted to distorted MO6/2 octahedra about the orthorhombic b-axis, (2) the size of polaronic holes decreases progressively with r3+ from about ten Ti sites in LaTiO3 to small polarons in GdTiO3, (3) the strength of the R–O–Ti interactions increases with the spin of the R3+ ion in the ferromagnetic compounds, (4) the saturation magnetization of the ferromagnetic TiO3 array at 5 K and the Curie temperature TC both increase with decreasing r3+ where the R3+ ions have no spin, and (5) there is no evidence of 'cluster-glass' behaviour where there is no variance of the R3+-ion radii The cooperative Jahn–Teller orbital ordering and small-polaron behaviour of the ferrimagnetic and ferromagnetic compounds would favour localized Ti-3d electrons However, the lack of saturation to 1 μB/Ti of the ferromagnetic TiO3 array in the absence of a spin on the R3+ ion suggests a separation of an orbitally ordered ferromagnetic phase and an orbitally disordered paramagnetic phase
TL;DR: Large-amplitude magnetic solitary waves are computed, which help explain recent spin-torque experiments, and the mode's nonlinear frequency shift is found by use of perturbation techniques, whose results agree with those of direct numerical simulations.
Abstract: A nonlinear model of spin-wave excitation using a point contact in a thin ferromagnetic film is introduced. Large-amplitude magnetic solitary waves are computed, which help explain recent spin-torque experiments. Numerical simulations of the fully nonlinear model predict excitation frequencies in excess of 0.2 THz for contact diameters smaller than 6 nm. Simulations also predict a saturation and redshift of the frequency at currents large enough to invert the magnetization under the point contact. The theory is approximated by a cubic complex Ginzburg-Landau type equation. The mode's nonlinear frequency shift is found by use of perturbation techniques, whose results agree with those of direct numerical simulations.
TL;DR: In this article, the formal oxidation state of Cr is +3 throughout the films, with no evidence for either elemental Cr or half-metallic CrO2, with uniform distribution throughout the doped region of the film.
Abstract: Epitaxial ferromagnetic films of Cr-doped TiO2 anatase (CrxTi1−xO2−x∕2) were grown on LaAlO3(001) using oxygen-plasma-assisted molecular-beam epitaxy. CrK-shell x-ray absorption near-edge spectroscopy shows that the formal oxidation state of Cr is +3 throughout the films, with no evidence for either elemental Cr or half-metallic CrO2. Cr is found to substitute for Ti in the lattice, with uniform distribution throughout the doped region of the film. The Cr-doped anatase films exhibit room-temperature ferromagnetism aligned in-plane, with a saturation magnetization of ∼0.6μB/Cr atom.
TL;DR: In this paper, a poly crystalline nickel-zinc-titanium ferrite with varied quantities of indium was synthesized under optimum preparatory conditions and the results indicated definite improvements in resistivity and saturation magnetisation.
TL;DR: In this article, the DC dielectric breakdown strength of magnetic fluids based on transformer oil TECHNOL US 4000, with different saturation magnetizations, was investigated in various orientations of external magnetic field.
TL;DR: In this paper, a pulse electrodeposition method for preparing stress-free CoFeB thin films is described, which is optimized to produce amorphous films with soft magnetic properties and the best composition was found to be Co 94 Fe 5 B 1.
TL;DR: In this paper, the authors report on the magnetic characterization of thin films composed of gas-phase cobalt nanoclusters deposited on surfaces and show that at ambient temperature, there is a strong exchange interaction between the clusters, while at cryogenic temperatures an exchange bias field appears.
Abstract: In this work we report on the magnetic characterization of thin films composed of gas-phase cobalt nanoclusters deposited on surfaces. Measurements of magnetization curves at ambient temperature indicate a strong exchange interaction between the clusters, while at cryogenic temperatures an exchange bias field appears. The latter confirms the existence of a ferromagnetic/antiferromagnetic core-shell system. Temperature-dependent magnetization measurements under zero-field-cooled conditions showed a rather broad maximum situated around 200 K. Magnetic force microscopy indicates the formation of a correlated super-spin-glass sCSSGd resulting from the frustration between the interparticle exchange interaction and the randomly oriented intraparticle anisotropy. The approach to saturation of the magnetization curves at 295 K is consistent with a CSSG.
TL;DR: X-ray photoemission electron microscopy is used to probe the remnant magneticdomain structure in high quality, single-crystalline, exchange-biased Fe/MnPd bilayers and it is found that the induced unidirectional anisotropy strongly affects the overall magnetic domain structure.
Abstract: X-ray photoemission electron microscopy is used to probe the remnant magnetic domain structure in high quality, single-crystalline, exchange-biased Fe/MnPd bilayers. It is found that the induced unidirectional anisotropy strongly affects the overall magnetic domain structure. Real space images of the ferromagnetic domains provide direct evidence for an asymmetric magnetization reversal process after saturation along the ferromagnetic hard direction. The magnetization reversal occurs by moment rotation for decreasing fields while it proceeds by domain nucleation and growth for increasing fields. The observed domains are consistent with the crystallography of the bilayers and favor a configuration that minimizes the overall magnetostatic energy of the ferromagnetic layer.
TL;DR: In this paper, a (Mn, Co)-codoped ZnO films were synthesized on c-sapphire by a radio-frequency magnetron sputtering system in which two targets were sputtered together.
Abstract: (Mn, Co)-codoped ZnO films have been synthesized on c-sapphire (0001) by a radio-frequency magnetron sputtering system in which two targets were sputtered together. X-ray-diffraction measurements indicate that the films are highly c-axis oriented. X-ray photon spectra show that the doped Mn and Co ions in (Mn, Co) ZnO films are both in the divalent states. The films show ferromagnetic behavior with a coercivity of about 90 Oe and a saturation moment of 0.11μB∕(0.3Mn2++0.7Co2+) at 300 K. In the lower temperatures between 5 and 20 K, a relatively large positive magnetoresistance over 10% was observed for (Mn0.03,Co0.07)Zn0.90O film. The number of carrier concentration is experimentally established to be 1.5613×1018cm−3 and the mobility to be 2.815cm2V−1s−1 for (Mn0.03,Co0.07)Zn0.90O film by Hall measurements at 300 K. The origins of the room-temperature magnetism and the large positive magnetoresistance are also discussed.
TL;DR: In this article, it was shown that gain saturation due to carrier depletion can be eliminated by increasing the SOA pump current density, and that the saturation power for cw amplification can be enhanced by two orders in magnitude in QD SOAs.
TL;DR: The temperature dependence of the lowest order magnetic anisotropy constant K1 and lowest order saturation magnetostriction constant, (3∕2)λ100, were measured from 4 K to 300 K for Fe91.4Ga8.6,Fe83.4 Ga16.6 and Fe71.5Ga28.5 and were compared to the normalized magnetization power law as mentioned in this paper.
Abstract: The temperature dependence of the lowest order magnetic anisotropy constant K1 and the lowest order saturation magnetostriction constant, (3∕2)λ100, were measured from 4 K to 300 K for Fe91.4Ga8.6,Fe83.4Ga16.6, and Fe71.5Ga28.5 and were compared to the normalized magnetization power law, ml(l+1)∕2. Fe91.4Ga8.6 maintains the magnetostriction anomaly of Fe (dλ100∕dT>0) and K1 is a reasonable fit to the ml(l+1)∕2 power law with K1(0K)≅90kJ∕m3. Fe83.4Ga16.6 does not show a magnetostriction anomaly, but fits the power law remarkably well. Fe71.5Ga28.5 possesses a small K1(∼1kJ∕m3) at all temperatures and a large temperature dependent magnetostriction, reaching ∼800ppm at low temperature.
TL;DR: In this paper, the magnetic properties of Mn-doped ZnO (Zn 0.98 Mn 0.02 O) bulk materials were investigated by measuring magnetization as functions of temperature and magnetic field.
04 Apr 2005
TL;DR: In this paper, a bilayer made up of a hard (FePt) and soft (Fe) phase coupled by exchange interactions is fabricated with the easy-magnetisation direction perpendicular to the film plane.
Abstract: A bilayer made up of a hard (FePt) and soft (Fe) phase coupled by exchange interactions is fabricated with the easy-magnetisation direction perpendicular to the film plane. Structural characterization is performed by means of X-ray diffraction, X-ray reflectivity and transmission electron microscopy. The films morphology is investigated by atomic force microscopy and their magnetic properties are studied at room temperature by an alternating gradient force magnetometer. A high surface roughness and the compositionally homogeneous FePt layer is found. Consistent with the observed microstructure, the hysteresis loops measured on the FePt film show a strong orientation with high uniaxial anisotropy, and perpendicular coercivity while that of the FePt/Fe bilayer exhibits an increase in saturation magnetisation, remanence, and energy product.
01 Jan 2005
TL;DR: In this paper, the authors describe the properties of superconducting materials and their applications in computer simulation, including magnetic energy storage, magnetoelastic effects, and flux creep phenomena.
Abstract: Selected articles. AC applications of superconducting materials. AC losses in superconducting materials. Amorphous superconductors. Anisotropy in magnetic materials. Anisotropy in superconducting materials. Biomagnetic measurements. Chevrel phases. Coercivity and domain wall pinning. Coherence length, proximity effect and fluctuations. Design with magnetic materials. Design with magnetic materials: computer simulation. Domains and domain walls. Ferrites, hard. Fluids, magnetic. Flux creep phenomena. Flux pinning and the summation of pinning forces. Granular superconductors. High-frequency impedance of superconducting materials. High-frequency properties of magnetic materials. Josephson effects in weak links. Magnetic energy storage. Magnetic properties of superconductors. Magnetic separation. Magnetic storage media. Magnetic units and material specification. Magnetization imaging. Magnetocaloric effect. Magnetoelastic phenomena. Magnetooptic materials. Magnetooptic storage media. Millimeter-wave detection. Multifilamentary superconducting composites. Nanocrystalline soft magnetic materials. Niobium-titanium alloys. Nonequilibrium superconductivity. Nuclear magnetic resonance imaging. Optical properties of superconductors. Organic and molecular ferromagnets. Oxide glasses as magnetic materials. Oxide superconductors: ceramic processing. Oxide superconductors: physical properties. Oxide superconductors: thin-film deposition. Power loss in magnetic materials. Radiation effects on magnetic materials. Radiation effects on superconducting materials. Superconducting magnets. Superconducting materials: BCS and phenomenological theories. Thin films and multilayers, magnetic.
TL;DR: In this article, the authors employed a combination of theory and full particle simulations, including one for realistic mass ratio, to address the saturation of a single, linearly unstable tearing mode as a function of guide field.
Abstract: [1] The tearing instability has been the subject of much study in space and laboratory plasmas and is thought to play a role as an onset mechanism for reconnection at the magnetotail and at the magnetopause. However, the nonlinear evolution is not completely understood. Here we employ a combination of theory and full particle simulations, including one for realistic mass ratio, to address the saturation of a single, linearly unstable tearing mode as a function of guide field. For the parameter regime considered, we find no agreement with any of the previous theories of tearing mode saturation. There are marked differences in the electron behavior and the associated saturation mechanism in the antiparallel (zero guide field) and finite guide field cases. Electrons become nongyrotropic and also develop temperature anisotropies in the antiparallel case, whereas they remain isotropic in the presence of a guide field. In the antiparallel limit there are two competing saturation mechanisms. One is due to preferential parallel heating of electrons which leads to a saturation amplitude of ws ∼ 2.9 ρe, where ρe is the electron gyroradius in the asymptotic magnetic field and ws is the half-width of the magnetic island. The other saturation mechanism is electron trapping in the magnetic island which leads to a saturation amplitude comparable to the singular layer thickness (ΔNS). Electron parallel heating is usually the dominant saturation mechanism. However, in the presence of sufficiently fast electron pitch angle scattering, caused either by current-aligned Weibel instability or turbulence, the second saturation mechanism due to trapping becomes dominant. In the presence of a guide field, the only saturation mechanism is electron trapping which leads to a saturation amplitude of ws ∼ 1.8 ρeG in the strong guide field and ws ∼ (2ρeGΔNS)1/2 in the intermediate regime. Here ρeG is the electron gyroradius in the guide field. The predicted saturation amplitudes for all cases, including the antiparallel regime, are much smaller than the thickness of the magnetopause current layer. Thus a single tearing mode saturates at too small of an amplitude to be of relevance to reconnection in the magnetosphere.
TL;DR: In this article, the properties of Mn-doped ZnO (Zn0.98Mn 0.02O) bulk materials were investigated by measuring magnetization as functions of temperature and magnetic field.
Abstract: Magnetic properties of Mn-doped ZnO (Zn0.98Mn0.02O) bulk materials prepared by the solid-state reaction method were investigated by measuring magnetization as functions of temperature and magnetic field. The special feature of our sample preparation was the low-temperature processing. When high-temperature (T>700°C) was used, secondary phase was found. The results indicate that the samples sintered in Ar gas show ferromagnetic behavior at room temperature, but it disappears in samples sintered in air. Even for ferromagnetic samples, the obtained saturation value of magnetization is much smaller than the theoretical value, suggesting the possibility that there is a strong antiferromagnetic exchange coupling in this kind of compound.
TL;DR: In this article, a saturation magnetostriction of 5-layered modulated martensite (5 M) was determined from magnetization curves and by using direct measurements of the field-induced strain of strongly constrained single crystalline sample.