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Showing papers on "Magnetic anisotropy published in 1980"


Journal ArticleDOI
TL;DR: In this article, it was shown that the anisotropy field maintaining the remanent magnetization in the direction of the initial applied field is strongly enhanced by the addition of nonmagnetic Au or Pt impurities.
Abstract: Recent measurements on $\mathrm{Cu}\mathrm{Mn}$ spin-glass alloys have revealed that the anisotropy field maintaining the remanent magnetization in the direction of the initial applied field is strongly enhanced by the addition of nonmagnetic Au or Pt impurities. We show that these results can be accounted for by the existence of Dzyaloshinsky-Moriya-type interactions between the Mn spins arising from spin-orbit scattering of the conduction electrons by nonmagnetic impurities. The magnitude of these interactions is surprisingly large.

566 citations


Book ChapterDOI
TL;DR: In this article, a general treatment of magnetostriction for the cases of hexagonal and cubic symmetry is described, which is applicable to the rare earth elements and rare earth-iron compounds and the role of intrinsic as well as extrinsic effects.
Abstract: Publisher Summary This chapter provides an overview of the magnetoelastic properties of the highly magnetostrictive rare earth-Fe2 alloys. The chapter describes a general treatment of magnetostriction for the cases of hexagonal and cubic symmetry, which is applicable to the rare earth elements and the rare earth-iron compounds. The chapter presents the magnetostriction of binary rare earth-iron alloys and the magnetostriction of single crystal and polycrystal RFe2 compounds are compared to other magnetostrictive materials at room temperature. The chapter discusses a possible source of startling magnetostriction anisotropy, measurements of magnetization, sublattice magnetization, and magnetic anisotropy, and the role of intrinsic as well as extrinsic effects. It reports the effects of the strong magnetoelastic coupling on sound velocities and elastic moduli and observes extraordinarily large ∆E effects and changes in sound velocity in single crystals, polycrystals, and amorphous rare earth-Fe2 alloys. The chapter concludes with a discussion of the recent measurements of linear and volume magnetostriction on the amorphous form of the RFe2 alloys.

319 citations


Book
01 Jan 1980
TL;DR: In this paper, the authors present a detailed analysis of the properties of magnetic bubble films and their properties as well as their properties in terms of anisotropy energy density and growth anisotropic energy density.
Abstract: 1. Introduction to Magnetic Bubbles.- 1.1 What Are Magnetic Bubbles?.- 1.2 Available Bubble Materials.- 1.3 How Can Bubbles be Manipulated?.- 1.4 Why Are Bubbles of Practical Interest?.- 1.5 A Typical Storage Device.- 1.6 Why Are Bubbles of Scientific Interest?.- 1.7 Scope and Organization of the Book.- 1.8 History.- 1.9 Summary.- 2. Static Properties of Magnetic Bubbles.- 2.1 Fundamental Characteristics of the Bubble Film.- 2.1.1 Magnetic Interactions.- a) Exchange Energy Density, Ex.- b) Demagnetization Energy Density, ED.- c) Anisotropy Energy Density, EK.- d) Magnetic Field Energy Density, EH.- e) Magnetoelastic Energy Density, ES.- 2.1.2 Structural Characteristics of the Bubble Film.- 2.1.3 Anisotropy Energy Density.- a) Growth Anisotropy Density, EKG.- b) Crystalline Anisotropy Energy Density, EKC.- 2.1.4 Summary of Important Film Parameters.- 2.2 Bubble Domain Configurations.- 2.2.1 Equilibrium Configuration of a Small Segment of Domain Wall.- 2.2.2 Equilibrium Configuration of an Isolated Bubble.- 2.2.3 Influence of Permalloy Overlayers.- 2.2.4 Equilibrium Configuration of a Bubble Lattice.- 2.2.5 Bubble States.- 2.2.6 Hard Bubbles.- 2.3 Summary.- 3. Dynamic Properties of Magnetic Bubbles.- 3.1 Motion of a Wall.- 3.1.1 Description of Planar Wall Segments.- 3.1.2 Motion of an Uncoupled Magnetic Moment.- 3.1.3 Equation of Motion for a Planar Domain Wall Segment.- 3.1.4 Motion of an Infinite Planar Wall Without Bloch Lines.- 3.1.5 Motion of a Planar Wall Without Bloch Lines in a Film of Thickness, h.- 3.1.6 Motion of a Bloch Line in a Moving Bloch Wall.- 3.1.7 Summary of the Motion of Planar Walls.- 3.2 Motion of a Bubble.- 3.2.1 Bubble Mobility.- 3.2.2 Gyrotropic Bubble Deflection.- 3.2.3 Response of Bloch Lines to Bubble Motion.- 3.2.4 The Influence of the Film Surface.- 3.2.5 Bloch Line Phenomena.- 3.2.6 Influence of a Surface Cap.- 3.2.7 Influence of Orthorhombic Anisotropy.- 3.3 Summary.- 4. Basic Permalloy-Bar Bubble Devices.- 4.1 Propagation.- 4.1.1 TI Bar Propagation Model.- 4.1.2 TI Bar Propagation Margins.- 4.1.3 C Bar Propagation Margins.- 4.1.4 Failure Mechanisms in C Bar Propagation.- 4.2 Other Functional Elements.- 4.2.1 Generators.- 4.2.2 Switches.- 4.2.3 Sensors.- 4.3 Total Chip Performance.- 4.4 Device Scaling.- 4.5 Summary.- 5. Other Bubble Device Forms.- 5.1 Two-Level Permalloy Bar.- 5.2 Charged-Wall Bubble Devices.- 5.2.1 CD Propagation.- 5.2.2 Propagation on Ion-Implanted CD Patterns.- 5.2.3 The Influence of Anisotropy in the Implanted Layer.- 5.2.4 The Influence of Pattern Geometry.- 5.2.5 Other CD Device Functions.- 5.3 Bubble Lattice Devices.- 5.3.1 Review of Salient Features of Lattice Bubbles.- 5.3.2 Lattice Propagation.- 5.3.3 Other Lattice Functions.- 5.4 Current Sheet Devices.- 5.4.1 Dual Conductor (DC).- 5.4.2 Cross-Hatch (XH).- 5.5 Summary.- 6. Bubble Materials.- 6.1 The General Approach to Tailoring the Properties of Bubble Materials.- 6.2 Garnets.- 6.2.1 Crystal Structure and Lattice Spacing.- 6.2.2 Magnetization.- 6.2.3 Magnetic Anisotropy.- 6.2.4 Garnet Dodecahedral Sites.- 6.2.5 Dynamic Properties.- 6.2.6 Range of Garnet Properties.- 6.3 Hexaferrites.- 6.3.1 Crystal Structure.- 6.3.2 Magnetic Properties.- 6.4 Amorphous Materials.- 6.4.1 Similarities and Differences.- 6.4.2 Static Properties.- 6.4.3 Dynamic Properties.- 6.4.4 Summary.- 6.5 Orthoferrites.- 6.6 Summary.- 7. Device Chip Fabrication.- 7.1 Crystal Growth.- 7.1.1 Choice of Substrates.- 7.1.2 Czochralski Growth of Garnet Crystals.- 7.1.3 Critical Factors and Typical Values.- 7.2 Substrate Preparation.- 7.3 Film Growth.- 7.3.1 Film Growth Options.- 7.3.2 Dipping LPE Techniques.- 7.3.3 Crucial Factors and Potential Problems.- 7.3.4 Phenomena That Must be Understood and Controlled.- 7.3.5 Process Control.- 7.4 Fabrication of Device Structure.- 7.4.1 Typical Planar Process.- 7.4.2 Variations on the Process.- a) Process Variations in a Planar Structure.- b) Hard Bubble Suppression.- c) Nonplanar Structure.- d) Additive Electroplating.- e) SLM.- f) CD.- 7.4.3 Lithography.- 7.4.4 Potential Problems.- a) Stress.- b) Permalloy Domain Effects.- c) Electromigration.- d) Chemical Interaction.- 7.5 Summary.- 8. Chip Packaging.- 8.1 The Storage Unit.- 8.2 The Storage Module.- 8.3 Limitations on Module Size.- 8.4 Data Integrity.- 8.5 Module Testing.- 8.6 Summary.- 9. Applications.- 9.1 Useful Features of Bubble Devices.- 9.1.1 Intermediate Cost/Speed.- 9.1.2 Major/Minor Loop Organization.- 9.1.3 Lack of Momentum.- 9.1.4 Ladder Organization.- 9.2 General Purpose Storage Units.- 9.3 Storage Hierarchies.- 9.4 Special Purpose Applications.- 9.4.1 Repertory Dialer.- 9.4.2 Speech Announcement.- 9.4.3 Text Editing.- 9.4.4 Flight Recorder.- 9.5 Summary.- 10. Future Prospects.- 10.1 Dependencies of the Module Attributes.- 10.2 Constraints on Active Chip Area.- 10.3 Constraints on Device Cell Density.- a) Resolution of the Device Pattern Exposure System.- b) Resolution of the Device Structure Fabrication Method.- c) Electromigration.- d) Bubble Material Properties.- 10.4 Constraints on Operating Frequency.- 10.5 Loop Length.- 10.6 Areas for Future Research.- 10.7 Summary.- 11. Recent Developments.- 11.1 Contiguous Disk Bubble Devices.- 11.1.1 Charged Wall Bubble Propagation.- 11.1.2 Other Device Elements.- 11.1.3 Complementary Permalloy Devices.- 11.2 Permalloy Bar Storage Chips.- 11.3 Garnet Uniaxial Anisotropy, Ku.- 11.3.1 Ku by Preferential Distribution on Iron Sites.- 11.3.2 High Ku Using Bi Ions.- 11.3.3 Ion-Implantation Modification of Ku.- 11.4 Summary.- References.

284 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that an itinerant electron ferromagnet with no inversion symmetry is unstable against a helical spin density wave (HSDW) if a magnetic anisotropy energy is sufficiently small.

191 citations


Journal ArticleDOI
TL;DR: In this paper, a complete phenomenological analysis is given for the case of uniaxial anisotropy in terms of K1, K2, K3, K4, K5, K6, K7, K8, K9, K10, K11, K12, K13, K14, K15, K16, K17, K18, K19, K20, K21, K22, K23, K24, K25, K26, K27, K28, K29, K30,

182 citations


Journal ArticleDOI
TL;DR: In this article, the authors used the Bitter technique to observe magnetization distribution in the Co-Cr medium, and the transition of magnetization was directly observed on the top and bottom surfaces of the film.
Abstract: The extremely high resolution properties in a perpendicular magnetic recording system were studied with a recently developed Co-Cr film medium. Bitter technique was used to observe magnetization distribution in the medium, and the transition of magnetization was directly observed on the top and the bottom surfaces of the film. It was proved that an ideal perpendicular magnetization mode, having a very narrow transition width, takes place even in a high recording density over 40 kBPI. From the angular variation of H c and the micro-structure of the Co-Cr film, it was concluded that the high recording resolution of the film results from the fine columnar particles which show the rotational mechanism of magnetization reversal accompanied by a perpendicular magnetocrystalline anisotropy. The Co-Cr film was also found to be superior in perpendicular anisotropy to any other Co-M films studied here in.

116 citations


Journal ArticleDOI
TL;DR: In this article, the authors measured the hysteresis cycle of the magnetization of CuMn 1 % in the spin glass state as a function of the concentration of a non magnetic impurity.
Abstract: 2014 Measurements of the hysteresis cycle of the magnetization of CuMn 1 % in the spin glass state as a function of the concentration of a non magnetic impurity show that the width of the hysteresis is proportional to the concentration of Au at a rate of 6.2 ± 0.4 kOe/at. % Au. A much smaller rate observed for Al and Ag and higher rate observed for Pt demonstrate unambiguously that the spin orbit interaction is responsible for the anisotropy field in the spin glass state. A comparison is made with similar alloys studied by spin resonance by Okuda and Date and some implication are discussed. J. Physique 41 (1980) 427-435 MAI 1980,

101 citations


Journal ArticleDOI
TL;DR: In this article, the magnetic reflection data was interpreted satisfactorily by considering a triangular spin structure of helically modulated ferromagnetic chains: the magnetic moments lie in the c-plane and rotate by 5.1±0.1° along the chain or the axis, while the moments rotate by 120° in the plane.
Abstract: Neutron diffraction measurements were made on single crystals of CsCuCl 3 . The sense of Cu 2+ ion helix was found from nuclear reflections to be predominantly right-handed. The magnetic reflection data could be interpreted satisfactorily by considering a triangular spin structure of helically modulated ferromagnetic chains: The magnetic moments lie in the c-plane and rotate by 5.1±0.1° along the chain or the c-axis, while the moments rotate by 120° in the c-plane. The magnitude of the magnetic moment is 0.58±0.01 µ B at 4.2 K. The critical exponent of the magnetization, β was found to be 0.358±0.015 around the Neel temperature, 10.70±0.05 K. We present a model that the helical modulation along the c-axis is caused by the antisymmetric exchange (Dzyaloshinsky-Moriya) interaction characteristic of the crystal symmetry of CsCuCl 3 . The model predicts a right-handed magnetic helix in the present case.

97 citations


Journal ArticleDOI
TL;DR: In this article, a magnetic phase diagram for CeB6 has been proposed and the paramagnetic susceptibility has been analyzed by assuming appropriate values of crystal-field splitting and exchange interactions.

93 citations


Journal ArticleDOI
R. Potter1, I. Beardsley
TL;DR: In this article, a comparison of perpendicular and longitudinal recording indicates that conventional heads are suitable for recording on high coercivity media having perpendicular magnetic anisotropy, at equal bit shift and head to disk separation perpendicular recording gives a factor of 2.5 increase in the linear density attained with media in use today.
Abstract: A comparison of perpendicular and longitudinal recording indicates that conventional heads are suitable for recording on high coercivity media having perpendicular magnetic anisotropy. At equal bit shift and head to disk separation perpendicular recording gives a factor of 2.5 increase in the linear density attained with media in use today.

84 citations


Journal ArticleDOI
TL;DR: In this article, specific heat measurements have been performed on single crystals of CeSb with a magnetic field up to 70 kOe applied along a (001) direction, and the results confirm that in some magnetic structures there exist non-magnetic planes in which Ce3+ ions have an entropy of about kln2.
Abstract: Specific heat measurements have been performed on single crystals of CeSb with a magnetic field up to 70 kOe applied along a (001) direction. These results confirm that in some magnetic structures there exist non-magnetic planes in which Ce3+ ions have an entropy of about kln2.

Journal ArticleDOI
06 Mar 1980-Nature
TL;DR: In this paper, an effect whereby an anisotropic magnetic material acquires a remanence on exposure to an alternating magnetic field was predicted from an analysis of the phenomenon of rotational remanent magnetisation (RRM).
Abstract: An effect whereby an anisotropic magnetic material acquires a remanence on exposure to an alternating magnetic field (a.f.) is predicted from an analysis of the phenomenon of rotational remanent magnetisation (RRM). The remanence, which is of gyromagnetic origin, is produced even when there is no relative rotation between sample and field and all constant fields have been eliminated. The effect is demonstrated in magnetic recording tape and, as well as having important implications for a.f. demagnetisation techniques, may be relevant to magnetic recording processes.

Journal ArticleDOI
TL;DR: In this article, the magnetic ordered phase of the CeIn3 compound is shown to be an antiferromagnetic one with a propagation vector ( 1 2, 1 2, 1 2 ) and a weak value of the magnetic moment 0.48±0.08 μB.

Journal ArticleDOI
TL;DR: In this article, the amorphous Fe40Ni40P14B6 alloy (Metglas 2826) has been annealed under magnetic field at several temperatures and the kinetics of induced magnetic anisotropy exhibits a broad spectrum (β = 4) of time constants; it obeys exactly an Arrhenius law with an activation energy of 1.74 ± 0.04 eV.

Journal ArticleDOI
TL;DR: In this paper, the authors studied the room temperature dependence of the stress-induced magnetic anisotropy in Co 73 Mo 2 Si 15 B 10 (λ s 0.89 Fe 0.11 ) 72 Mo 3 Si 15B 10(λ > 0) metallic glass ribbons and concluded that transient creep and steady-state creep at the elevated temperature give rise to compressive and tensile stresses, respectively, in the expression for the magnetoelastic coupling energy at room temperature.

Journal ArticleDOI
TL;DR: The magnetic properties of Laves phase compound PrFe2, synthesized at high pressure, were studied by Mossbauer spectroscopy and saturation magnetisation as discussed by the authors, and the ferromagnetism in the compound was confirmed.
Abstract: The magnetic properties of Laves phase compound PrFe2, synthesised at high pressure, were studied by Mossbauer spectroscopy and saturation magnetisation. The ferromagnetism in PrFe2 has been confirmed. The rotation of the easy axis of magnetisation on the (110) plane to (111) with respect to (001) was observed as temperature increased. The authors have calculated the single-ion crystalline field magnetic anisotropy and have found this model to account for the experimental results in principle.

Journal ArticleDOI
TL;DR: Ferromagnetic resonance and antiresonance experiments have been performed on (100) planes of iron whiskers in order to determine the value of surface anisotropy Ks as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, the average moments and the moment disturbances of ferromagnetic Ni-Pt alloys with concentrations of 20, 30, 40, 50, 55, and 57 at.% Pt have been measured by the magnetic diffuse scattering of neutrons.
Abstract: The average moments and the moment disturbances of ferromagnetic Ni-Pt alloys with concentrations of 20, 30, 40, 50, 55, and 57 at.% Pt have been measured by the magnetic diffuse scattering of neutrons. The data have been analyzed with the linear superposition model of Marshall including short-range order. The data have also been discussed in terms of Medina's chemical-magnetic environment model which assumes that the moment on an Ni atom is a function of the magnetic moments of the surrounding atoms and of its nearest chemical environment. The results show that the average Ni moment decreases with increasing Pt concentration, while Pt has an average moment of about half that of Ni. The moment disturbance functions, corrected for short-range order, show peaks in the forward direction corresponding to inhomogeneous-moment distributions which may be described as ferromagnetic clusters. The analysis of the data with the chemical-magnetic environment model shows that most of the moment disturbances are caused by the magnetic environment in accordance with other Ni-based alloys. An apparent difference in the macroscopic magnetization of these systems is attributed to differences in chemical short-range order rather than to a different mechanism for the onset of ferromagnetism.

Journal ArticleDOI
TL;DR: In this paper, the electric susceptibility of samples of ferrofluids subjected to a uniform magnetic field H was measured and interpreted as a magneto-electric directive effect, based on the assumption that the magnetic particles are roughly ellipsoidal and conducting grains.
Abstract: The electric susceptibility of samples of ferrofluids subjected to a uniform magnetic field H was measured. The electric susceptibility \chi is dependent on the magnitude of the magnetic field and on the relative direction between the electric field E and the magnetic field H . 1) When E is perpendicular to H, \frac{\partial\chi_{\perp}}{\partialH} 2) When E is parallel to H, \frac{\partial\chi_{\parellel}}{\partialH} > 0 These results have been interpreted as a magneto-electric directive effect. A model is proposed, based on the assumption that the magnetic particles are roughly ellipsoidal and conducting grains.

Journal ArticleDOI
TL;DR: In this paper, a biaxial magnetic anisotropy in Co73Mo2Si15B10 (γs 0) metallic glass ribbons has been induced by strain annealing and by field anneeling above and below the Curie-temperature, respectively.

Journal ArticleDOI
TL;DR: In this article, the magnetic moment in every phase at 4.2 K was determined by applying magnetic field along the crystalline b axis, and the results were confirmed with the Kitano-Nagamiya theory in the fan state.
Abstract: Neutron diffraction studies on the magnetic phase transition have been carried out by using single crystal of MnP. Successive phase transitions from screw, fan and ferromagnetic long range order were confirmed by applying magnetic field along the crystalline b axis. The magnetization measurements which give a saturation value of 1.33±.01 µ B per Mn atom afford experimental derivation of the absolute cross section for all the magnetic reflections. This provides us the exact value of the magnetic moment in every phase at 4.2 K. The controversy is eliminated completely; there is no change of the magnetic moment through the screw-fan transition, and the circular helix is concluded. The quantitative agreement of the present results is achieved with Kitano-Nagamiya theory in the fan state. The field dependence of the wave vector Q a of the fan state implies an additional evidence of the band character inherent in MnP.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the development of magnetic anisotropy with regard to thickness in amorphous electrolytic Co-P alloys in the range of thickness between 0.06-7.00μm.
Abstract: The development of magnetic anisotropy with regard to thickness in amorphous electrolytic Co-P alloys (15 at % P) has been observed in the range of thicknesses between 0.06-7.00μm. The study has been undertaken starting from the ratio M r /M s of the hysteresis loops. The results obtained indicate that for thicknesses below 4000 A the samples show an axis of easy magnetization in the plane. In the case of greater thicknesses, the axis of easy magnetization develops gradually out of the plane, reaching a perpendicular position near 10 μm. Our results suggest that what we are dealing with here is a shape anisotropy such as that proposed by Cargill, III et al.

Journal ArticleDOI
TL;DR: In this paper, two different kinds of magnetic annealing were made for zero magnetostrictive amorphous Fe-Co-Si-B alloy with high saturation induction (10.1 kG).
Abstract: Two different kinds of magnetic annealing were made for zero magnetostrictive amorphous Fe-Co-Si-B alloy with high saturation induction (10.1 kG). In a case of conventional magnetic annealing dc coercive force decreases to 12 mOe and maximum permeability increases as much as 8 × 105. But initial permeability at 1 kHz decreases to 500. Because of induced magnetic uniaxial anisotropy, magnetization can reverse easily by 180° wall motion in dc field, but in ac field magnetization reversal through 180° wall motion increases eddy-current loss and initial permeability decreases. In order to improve permeability in the ac field without inducing anisotropy, another kind of magnetic annealing was performed. The samples were rotated in a dc field and were annealed. We first got high initial ac permeability alloy with high saturation induction for the T_{c} > T_{cry} type. Initial ac μ at 1 kHz, coercive force, and remanence are 12000, 13 mOe, and 5.8 kG, respectively.

Journal ArticleDOI
TL;DR: In this article, the authors studied the diagrams of anisotropic n-component d-dimensional magnetic systems with a uniaxially random magnetic field along the easy axis, and found that for very weak anisotropy, a bicritical point appeared in the phase diagram.
Abstract: Mean-field and renormalisation group theories are used to study the diagrams of anisotropic n-component d-dimensional magnetic systems with a uniaxially random magnetic field along the easy axis. For strong anisotropy only the longitudinal phase exists. The transition into this phase exhibits a tricritical point. When the anisotropy is decreased, a 'transverse' or 'spin-flopped' phase appears for low temperatures and large values of the random field. This phase is separated from the longitudinal one by a spin-flop first-order line, ending at a critical end-point. For very weak anisotropy, a bicritical point appears in the phase diagram. For a certain value of the anisotropy the critical end-point, the bicritical point and the tricritical point all coincide defining a new multicritical point.

Journal ArticleDOI
TL;DR: In this paper, the magnetic anisotropy within the easy plane was investigated by torque measurements on NiO platelets which can be made fully free of antiferromagnetic domain walls.
Abstract: Magnetic anisotropy within the easy plane (111) is investigated by torque measurements on NiO platelets which can be made fully free of antiferromagnetic domain walls. The anisotropy constant K2 and the critical field for spin flopping Hc are determined in a temperature range from 288K to the Neel point, 523K. The difference of the perpendicular and parallel susceptibilities Delta chi = chi perpendicular to - chi /sub /// is also determined at temperatures from 77 to 523 K, using the magnetic torque measurements. At room temperatures (305K), K2 is found to be 44 erg g-1, and Hc amounts to 16.0 kOe, in agreement with the results of the proceeding optical observations. The susceptibility data indicate that the temperature-independent perpendicular susceptibility chi perpendicular to is 9.1*10-6 emu g-1.

Journal ArticleDOI
TL;DR: In this paper, the phase diagrams of the most typical quasi-one-dimensional antiferromagnet (CH 3 ) 4 NMnCl 3 (T N = 0.835 K) were investigated in more detail by heat capacity and magnetic susceptibility measurements in external magnetic fields up to 30 kOe.
Abstract: Magnetic phase diagrams of the most typical quasi-one-dimensional antiferromagnet (CH 3 ) 4 NMnCl 3 ( T N =0.835 K) reported in our previous paper have been investigated in more detail by heat capacity and magnetic susceptibility measurements in external magnetic fields up to 30 kOe. The phase diagrams for the external field applied along the in-plane easy and hard axes normal to the magnetic chain are reproduced satisfactorily by the theory in which the classical anisotropic XY model is assumed for the magnetic chain and interchain interarctions are treated within the molecular field approximation. The magnitude of the anisotropy field in the plane normal to the chain is determined to be 93 Oe.

Journal ArticleDOI
TL;DR: In this article, the first discussion of a long-wavelength, magnetostatic, surface spin-wave mode on uniaxial antiferromagnets is presented, and the frequency of the surface wave depends on the angle between the direction of propagation and the easy axis.
Abstract: The first discussion of a long-wavelength, magnetostatic, surface spin-wave mode on uniaxial antiferromagnets is presented. In the absence of an applied field, the frequency of the surface wave depends on the angle between the direction of propagation and the easy axis. With a magnetic field applied parallel to the surface, and along the easy axis, the surface mode does not propagate in all directions, but is limited to a restricted set of angles.

Journal ArticleDOI
TL;DR: In this article, the results of neutron powder diffraction and magnetic measurements on single crystals of CsMnI3 are reported, and the magnetic moment as found from neutron diffraction extrapolated to 0 K is 3.7(1)μB, indicating a considerable zero-point spin reduction.

Journal ArticleDOI
TL;DR: In this article, the low temperature magnetisation of a system of fine cobalt particles dispersed in toluene has been measured and a value of the effective anisotropy constant K = (1.9±0.5) × 106ergs/cc (at 40K) is obtained.
Abstract: The low temperature magnetisation of a system of fine cobalt particles dispersed in toluene has been measured. The remanence decays logarithmically with temperature. From these results a value of the effective anisotropy constant K = (1.9±0.5) × 106ergs/cc (at 40K) is obtained. Theory is presented to show that the magnetisation on approach to remanence is linear with H. From the gradient a second estimate of the anisotropy constant can be obtained at 77K having a value of K = (1.6±0.5) × 106erg/cc. These values which are much larger than would be expected for f.c.c, cobalt are consistent with the presence of dominant uniaxial shape anisotropy. This conclusion is supported by the observed remanence to saturation ratio of 0.5 at 0 K.

Journal ArticleDOI
TL;DR: Comparison of Mössbauer spectra obtained for the thalassemic heart tissue with those of normal heart tissue and of horse spleen ferritin identifies the iron deposits to be small, superparamagnetic particles of ferrite and/or hemosiderin, two closely related iron storage proteins containing an iron core of (FeOOH)8(FeO x OPO3H2).