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Magnetic structure
About: Magnetic structure is a research topic. Over the lifetime, 10787 publications have been published within this topic receiving 207143 citations.
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TL;DR: In this paper, it was shown that Van Vleck's susceptibility within the xy-plane is of twofold symmetry corresponding to O(x2)-y2 or Oxy.
Abstract: Exotic magnetism below TN17.5 K is studied within the level scheme where the lowest multiplet is a doublet within the 5f2 configuration. Effective g-factors of pseudo-spins with S = ½, which describe the degree of freedom of the doublet, are highly anisotropic: gx = gy = 0 for the xy-components and gz0 for the z-component. It is proposed that a recently discovered transition of first order at a critical pressure pc1.5 GPa is that between an ordered state of quadrupoles, with order parameter O(x2)-y2 or Oxy, below pc and an ordered state of dipoles, with order parameter Oz, above pc; pseudo-spins are ordered within the xy-plane below pc, and they are along the z-axis above pc. The proposal of this scenario is followed by many predictions. No static magnetic moments exist below pc. The anisotropy of Van Vleck's susceptibility within the xy-plane is of twofold symmetry corresponding to O(x2)-y2 or Oxy. What one observes by means of neutron diffraction and µSR (muon spin resonance) below pc are dynamically but slowly fluctuating magnetic moments. The softening of magnons occurs with pressures approaching pc below pc. Although static magnetic moments exist above pc, no magnon excitations can be observed there.
48 citations
TL;DR: In this article, the authors select a set of 20 magnetic clouds (MCs) observed by the spacecraft Wind and reconstruct their local magnetic structure from in situ observations under different models, and quantify their relative magnetic helicity per unit length (Hr/L) under the assumption of a cylindrical geometry.
48 citations
TL;DR: In this article, the structure-magnetic property correlations for a series of layered cobalt(II) compounds derived from the parent host Co(OH) 2 were discussed, where intercalation takes place by exchange of OH − by organic or inorganic anions resulting in interlayer spacing between 4.65 and 25.4 A.
48 citations
TL;DR: In this paper, the crystal structure and magnetic ordering of the Mn spins in polycrystalline NdMnO3 have been investigated by means of neutron diffraction and ac magnetic susceptibility measurements.
Abstract: The crystal structure and magnetic ordering of the Mn spins in polycrystalline NdMnO3 have been investigated by means of neutron diffraction and ac magnetic susceptibility measurements. The compound crystallizes into an orthorhombic symmetry of space group Pbnm. Three peaks were observed in the temperature dependence of the in-phase component of the ac susceptibility, χ′(T). Neutron diffraction measurements show that all three peaks observed in χ′(T) are of magnetic origin, and are associated with the ordering and the reorientation of the Mn spins. Both ferromagnetic and antiferromagnetic couplings between the Mn spins were observed, resulting in a noncollinear magnetic structure. The Mn spins order at Tm≈75 K, and the moment saturates at ∼20 K at 〈μz〉=2.21 μB.
48 citations
TL;DR: The structure is that of a compensated arrangement of moments within one layer, comprising one ferromagnetic and three antiferromagnetic superexchange pathways between the nickel atoms, and magnetic properties as a function of temperature and magnetic field are presented.
Abstract: We present the synthesis, characterization by DT-TGA and IR, single crystal X-ray nuclear structure at 300 K, nuclear and magnetic structure from neutron powder diffraction on a deuterated sample at 1.4 K, and magnetic properties as a function of temperature and magnetic field of Ni3(OH)2(SO4)2(H2O)2. The structure is formed of chains, parallel to the c-axis, of edge-sharing Ni(1)O6 octahedra, connected by the corners of Ni(2)O6 octahedra to form corrugated sheets along the bc-plane. The sheets are connected to one another by the sulfate groups to form the 3D network. The magnetic properties measured by ac and dc magnetization, isothermal magnetization at 2 K, and heat capacity are characterized by a transition from a paramagnet (C = 3.954 emu K/mol and θ = −31 K) to a canted antiferromagnet at TN = 29 K with an estimated canting angle of 0.2−0.3°. Deduced from powder neutron diffraction data, the magnetic structure is modeled by alternate pairs of Ni(1) within a chain having their moments pointing along ...
48 citations