Showing papers on "Magnetic structure published in 1983"
TL;DR: In this article, the use of small particles instead of thin films has some advantages for the study of the magnetic properties of surfaces, such as surface anisotropy and interfacial interactions.
158 citations
TL;DR: The magnetic behavior of eight samples of biotite and a lepidomelane was studied in the temperature range 15-300 K and analyzed in relation to their chemical composition as mentioned in this paper.
Abstract: The magnetic behavior of eight samples of biotite and a lepidomelane was studied in the temperature range 15–300 K and analyzed in relation to their chemical composition The platy morphology of biotite facilitates magnetic measurements with the applied field either in the plane of the sheets (Xe⊥ ) or perpendicular to the plane (Xe∥) At high temperature, the samples obey Curie‐Weiss laws, showing typical paramagnetic behavior which is due to the presence of both Fe2+ and Fe3+ ions However, the susceptibilities are anisotropic (χe⊥/χe∥≂125), because of a trigonal contribution to the crystal field which affects only the ferrous ions Formulae are given which permit the ferrous Curie‐Weiss parameters to be derived from the measured susceptibility At low temperature (T<10 K), three of the biotite samples containing high concentrations of iron (17 to 27 wt %) undergo an antiferromagnetic transition The magnetic structure consists of octahedral sheets of iron ions with their moments ferromagnetically co
69 citations
TL;DR: For spin-polarized low-energy electrons diffracted from ferromagnetic Ni(001), the exchange-and the spin-orbit-induced scattering asymmetries Aex and Aso of two diffracted beams have been simultaneously measured at T = 300 K and T = 520 K for several constant energies as functions of the polar angle of incidence as discussed by the authors.
56 citations
TL;DR: In this article, the magnetic structures of the antiferromagnetic layered compounds Co1/3NbS2 and Co 1/3TaS2 were examined using single-crystal neutron photographic and counting methods.
Abstract: The authors have examined the magnetic structures of the antiferromagnetic layered compounds Co1/3NbS2 and Co1/3TaS2 using single-crystal neutron photographic and counting methods. The magnetic structure of Co1/3NbS2 has been determined in detail, and has an orthohexagonal unit cell, containing two Co atoms, arranged on the 'hexagonal ordering of the first kind' scheme. The different symmetries of the crystallographic and magnetic unit cells leads to a complicated domain structure. A large part of the magnetisation in this material is localised on the Co atoms, although the magnetic moment of the Co2+ ion is approximately 10% lower than that of the corresponding spin-only moment. The magnetic structure of the related material, Co1/3TaS2, which has the same crystal structure as Co1/3NbS2, is very different, and is a triangular antiferromagnetic structure although for this material only the unit cell has been determined.
53 citations
TL;DR: In this article, the basic features of the magnetic structures of LaTiO3 and CeTiO 3 were determined by powder neutron diffraction and the most consistent interpretation is to assign G-type configuration to Ti(III) and an induced Fz on Ce(III).
51 citations
TL;DR: In this paper, the free energy, magnetic structure factor, and the Edwards-Anderson order parameter of a one-dimensional ferromagnetic Ising model in a random magnetic field are obtained.
Abstract: Analytic results for the free energy, magnetic structure factor, and Edwards-Anderson order parameter of a one-dimensional ferromagnetic Ising model in a random magnetic field are obtained. The structure factor consists of both Lorentzian and Lorentzian-squared terms at all temperatures ($T$) greater than zero; the Lorentzian-squared terms vanish at $T=0$. The calculated correlation length agrees with predictions of the Imry-Ma domain argument.
47 citations
TL;DR: The magnetic structure and weak ferromagnetism of Mn3Ge was studied by polarized neutron diffraction in this paper, and the magnetic structure was determined to have a triangular spin configuration in the c-plane with the symmetry reversed to the crystalline symmetry.
46 citations
TL;DR: In this paper, a neutron diffraction study of polycrystalline intermetallics was carried out at liquid helium temperature and the magnetic structure of these compounds consists of ferromagnetic layers perpendicular to the c-axis coupled antiferromagnetic with sequence +-+ −− for PrCu 2 Si 2 and +--+ for PrFe 2 Ge 2 and NdFe 2Ge 2.
45 citations
TL;DR: The first purely organic ferromagnet with a moment carried by the 2p electrons of the NO groups was considered for a long time and was considered to be the first pure organic magnet as discussed by the authors.
35 citations
TL;DR: In this article, a collinear antiferromagnetic order was found for the rare earths moments oriented along the c-axis of the compounds TbNi2Si2 (1), HoCo 2Si2(2) and TbCo 2 Si2 (3), and the corresponding wavevector were k = [12120] (1) andk = [ 0 0 1] (2)
32 citations
TL;DR: In this paper, structural, magnetization and Mossbauer measurements are reported on this paper2Si2 (RE = La, Ce, Nd, Gd, Er) compounds.
TL;DR: Magnetometric and neutron diffraction studies of polycrystalline NdCo 2 GE 2, ErCo 2 Ge 2 and PrFe 2 Ge2 compounds were carried out in the temperature range between 4.2 and 300 K.
TL;DR: In this article, the variation of antiferromagnetic order in the antimony isomorphous MnSb2O4 (TN ∼ 60 K) and NiSb 2O4(TN ∼ 46 K) has been studied.
TL;DR: In this paper, magnetic optical activity is reported in electronic resonance Raman transitions of OsBr, IrCl and U(C8H8)2 in solution, which can give detailed information about the magnetic structure of the ground and low-lying electronic states, particularly the sign of the g-factor and the ordering of magnetic sub-states.
Abstract: Magnetic optical activity is reported in electronic resonance Raman transitions of OsBr, IrCl and U(C8H8)2 in solution. All the effects are observed in the form of couplets which originate in separate Raman transitions between magnetic components of the initial and final levels. These can give detailed information about the magnetic structure of the ground and low-lying electronic states, particularly the sign of the g-factor and the ordering of magnetic sub-states in general. For example, effects in the 466 cm−1 electronic Raman band of U(C8H8)2 confirm that the MJ = ±4 level lies below the MJ = ±3 level. We also use the magnetic Raman optical activity to identify a very weak U(C8H8)2 Raman band at 675 cm−1 with a vibrational-electronic combination transition.
TL;DR: In this article, a single crystal of ytterbium orthoferrite at room temperature was studied and the relative value of the weak antiferromagnetic component Ay/Gx (hidden canting of the iron spins) was found to be 1.59(7)· 10 −2 in agreement with the theory.
TL;DR: In this paper, the crystal and magnetic structure of Rb2CrCl4, a compound that exhibits two-dimensional ferromagnetism with nearly easy-plane behaviour, has been investigated using single-crystal neutron diffraction at 5.5, 77 and 300K.
Abstract: The crystal and magnetic structure of Rb2CrCl4, a compound that exhibits two-dimensional ferromagnetism with nearly easy-plane behaviour, has been investigated using single-crystal neutron diffraction at 5.5, 77 and 300K. Selected Bragg reflections have also been examined at temperatures up to 573K. At all temperatures the structure is described by the space-group Cmca (D2h18), a subgroup of the K2NiF4 structure I4/mmm. There is an antiferrodistortive displacement of the Cl- ions in the basal plane such that the CrCl6 units are tetragonally elongated with principal axes alternately along (011) and (011) of the Cmca unit cell. At 5.5K the nearest-neighbour Cr-Cl distances are 2.700(7) and 2.387(6) AA within the basal plane and 2.371(22) AA parallel to the a axis. The ordered moments are canted alternately to one side and the other of the (010) or (001) axes of the Cmca cell by +or-(5.2+or-1.1 degrees ).
TL;DR: The analysis of the satellite structure of the NMR spin echo spectrum of the Mn 2 (V 1− v Al v )Al system suggests that V has a magnetic moment as mentioned in this paper.
TL;DR: In this article, the magnetic and crystallographic properties of the compounds CoMn 1− x Ti x Si (0⪕ x ⪕0.5) are studied by X-ray, neutron diffraction and magnetometric measurements.
TL;DR: An experimental and theoretical study of magnetic and structural transformations was carried out in NiMn as discussed by the authors, where the appearance of the antiferromagnetic structure is due to electron-hole pairing into a triplet state.
Abstract: An experimental and theoretical study of magnetic and structural transformations was carried out in NiMn. The appearance of the antiferromagnetic structure is shown to be due to electron-hole pairing into a triplet state, and the discovered ferromagnetic properties of NiMn alloyed with Fe are those of exciton ferromagnetism. The structural β-θ transition in NiMn is shown to be a magneto striction distortion of the lattice, the rhombic striction distortions are observed together with the tetragonal ones in a narrow temperature range and are due to the totology of the Fermi surface of NiMn.
TL;DR: In this article, the direction of the bulk spontaneous magnetization is very different from those of the cobalt and holmium magnetizations, and they compared the directions of these magnetizations with that of the conventional spontaneous magnetizations.
Abstract: Previous neutron diffraction studies have established the ferrimagnetic coupling of cobalt and holmium magnetic moments in HoCo5. However, owing to the competition of cobalt and holmium local anisotropies, which have opposite signs, a non-collinear magnetic structure is suggested at low temperatures. By combining magnetization measurements on a single crystal with Mossbauer and neutron diffraction experiments, we compared the directions of the cobalt and holmium magnetizations with that of the bulk spontaneous magnetization. Above 200 K all the magnetic moments are parallel to the c axis of the hexagonal structure. Below 200 K the magnetic structure becomes noncollinear owing to the reorientation of the magnetizations. The direction of the bulk spontaneous magnetization is very different from those of the cobalt and holmium magnetizations.
TL;DR: In this paper, the electronic structures of 15-atom clusters (Fe15, CoFe8Co6, FeCo8Fe6 and Co15) in the geometry appropriate to the bulk BCC metals and alloys have been determined from spin-polarised selfconsistent field X alpha scattered-wave calculations.
Abstract: The electronic structures of 15-atom clusters (Fe15, CoFe8Co6, FeCo8Fe6 and Co15) in the geometry appropriate to the bulk BCC metals and alloys have been determined from spin-polarised self-consistent field X alpha scattered-wave calculations. The general features of the results are quite similar to those obtained from band calculations for the bulk alloys. Examination of the local density of states on each atom and in each spin manifold has yielded a consistent and simple picture of the important interplay in these alloys between magnetic and chemical effects, the key factors being the greater electronegativity of Co and the larger magnetic moment and exchange splitting of Fe. The calculations lead to a qualitative explanation for the concentration dependence of the magnetisation, the volume and the thermal expansion coefficient, which show similar (though less dramatic) behaviour to that observed for the FCC Fe-Ni (Invar) alloys. Calculations of the contact hyperfine fields have led to a model in which the core contribution is proportional to the magnetic moment and the valence contribution depends on the moments of neighbouring atoms. The calculations have allowed some comments to be made on the effects of the order-disorder transition of these alloys on the volume, magnetisation and hyperfine fields.
TL;DR: Magnetization measurements of magnetic semiconductor Sn1-xCrxTe (x <5 at%) crystals with the Curie temperature Tc = 150-300 K were made down to 2 K as mentioned in this paper.
TL;DR: In this paper, the magnetic properties of CuxZn1−xCr2Se4 are explained in terms of the molecular field approximation assuming the existence of 90° exchange interactions, and the exchange parameters and integrals for the whole series under consideration are calculated.
Abstract: The magnetization, the susceptibility and the magnetic anisotropy field of Cu x Zn1−xCr2Se4 compounds have been studied at low temperatures (down to 2.9 K) in: high magnetic stationary fields (up to 14 T), high pulsed magnetic fields (up to 25 T), medium magnetic stationary fields (up to 0.6 T). The magnetic structure of these spinels was studied by neutron powder diffraction. The magnetic properties of CuxZn1−xCr2Se4 are explained in terms of the molecular field approximation assuming the existence of 90° exchange interactions, ferromagnetic for Cr-Se-Cr between the nearest Cr ions and antiferromagnetic for Cr-Se-Se-Cr between the second-nearest Cr ions. The exchange parameters and integrals for the whole series under consideration are calculated. Taking into account the three magnetic phase transitions observed in these spinels (Juszczyk, Krok, Okonska-Kozlowska, Broda, Warczewski, Byszewski, 1981) and the neutron diffraction studies a modification of the simple spin spiral forced by a strong m...
TL;DR: The magnetic structure of the tetragonal ErCo 2 Si 2 compound was determined by neutron diffraction on powder sample at 4.2 K as mentioned in this paper, where the magnetic ordering is connected with a symmetry lowering, magnetic space group P 2s 1 (Sh 7 2 ) k = 000.
TL;DR: In this article, the mechanism of transition from antiferromagnetic to ferromagnetic coupling by plastic deformation has been elucidated in terms of dislocation theory with consideration of ferromagnetism.
Abstract: It was found that in the long range ordered FePt 3 alloy, which showed no ferromagnetism before plastic deformation, the application of cold work caused it to become quite strongly ferromagnetic. The mechanism of transition from antiferromagnetic to ferromagnetic coupling by plastic deformation has been elucidated in terms of dislocation theory with consideration of ferromagnetic and antiferromagnetic Fe–Fe interactions. It has been proposed that the Fe atoms at the Pi-sites, being ferromagnetically coupled, is proportional to the dislocation density at the early stage of plastic deformation and its square root at the advanced stage.
TL;DR: Grunerite samples have been studied by Mossbauer and magnetic measurements to differentiate the hyperfine spectra of Fe 2+ in the four non-equivalent sites as discussed by the authors, and they can conclude: (i) T N = (46 ± 1) K; (ii) four different hyperfine fields are present at 4.2 K, and between 8.2 and 5 K, there is a sensitive change of the spectra; (iv) the grunerite magnetic structure consists of ferromagnetic chains coupled by weaker antiferromagnetic interactions.
TL;DR: In this paper, the magnetic moment direction was found to be slightly oblique away from the hexagonal c-axis on keeping the collinear two sublattice structure which is described by alternating up and down spin layers.
TL;DR: The magnetic structure and magnetic moments of Dy and Fe have been studied at 42 K by means of neutron diffraction measurements on powdered samples of Dy(Fe 1− x Al x ) 2 for x=10, 09, 03 (the C 15 structure) and for x =05, 12, 14, 16 for x≤09 is explained by the crystallographic disorder in the Fe-Al sublattice and lattice defects as mentioned in this paper.
TL;DR: In this article, the authors describe results on bulk magnetic properties, transition temperatures, magnetic structures and magnetic moments found for the NdAl x Ga 2 − x and ErAl x G 2 − X pseudoternary solid solution systems.
TL;DR: In this article, the magnetic structure of non-stoichiometric Fe 1− x O was investigated by neutron scattering measurements on a quenched single crystal of Fe 0.91 O below the Neel temperature.