Magnetic structure

About: Magnetic structure is a research topic. Over the lifetime, 10787 publications have been published within this topic receiving 207143 citations.

Magnetic structure of Cd-doped CeCoIn5

Abstract: The heavy-fermion superconductor CeCo In5 is believed to be close to a magnetic instability, but no static magnetic order has been found. Cadmium doping on the In site shifts the balance between superconductivity and antiferromagnetism to the latter with an extended concentration range where both types of order coexist at low temperatures. We investigated the magnetic structure of nominally 10% Cd-doped CeCo In5, being antiferromagnetically ordered below TN ≈3 K and superconducting below Tc ≈1.3 K, by elastic neutron scattering. Magnetic intensity was observed only at the ordering wave vector QAF = (1 2, 1 2, 1 2) commensurate with the crystal lattice. Upon entering the superconducting state, the magnetic intensity seems to change only little. The commensurate magnetic ordering in CeCo (In1-x Cdx) 5 is in contrast to the incommensurate antiferromagnetic ordering observed in the closely related compound CeRh In5. Our results give insights into the interplay between superconductivity and magnetism in the family of CeT In5 (T=Co, Rh, and Ir) based compounds. © 2007 The American Physical Society.

Ultrafast laser induced local magnetization dynamics in Heusler compounds.

Abstract: The overarching goal of the field of femtomagnetism is to control, via laser light, the magnetic structure of matter on a femtosecond time scale. The temporal limits to the light-magnetism interaction are governed by the fact that the electron spin interacts indirectly with light, with current studies showing a laser induced global loss in the magnetic moment on a time scale of the order of a few 100 s of femtoseconds. In this work, by means of ab-initio calculations, we show that more complex magnetic materials - we use the example of the Heusler and half-Heusler alloys - allow for purely optical excitations to cause a significant change in the local moments on the order of 5 fs. This, being purely optical in nature, represents the ultimate mechanism for the short time scale manipulation of spins. Furthermore, we demonstrate that qualitative behaviour of this rich magnetic response to laser light can be deduced from the ground-state spectrum, thus providing a route to tailoring the response of some complex magnetic materials, like the Heuslers, to laser light by the well established methods for material design from ground-state calculations.

Magnetic structure of LaCrO3 perovskite under high pressure from in situ neutron diffraction.

Abstract: The temperature-pressure phase diagram for both the crystal and magnetic structures of LaCrO(3) perovskite has been mapped out by in situ neutron-diffraction experiments under pressure. The system offers the opportunity to study the evolution of magnetic order, spin direction, and magnetic moment on crossing the orthorhombic-rhombohedral phase boundary. Moreover, a microscopic model of the superexchange interaction has been developed on the basis of the crystal structure obtained in this work to account for the behavior of T(N) under high pressure.

Magnetic order in ternary compounds RRh2Si2 and RRu2Si2

Abstract: Investigations by neutron diffraction and magnetic measurements are reported on the ternary suicides RRh2Si2 (R  Ce, Nd, Tb) and RRu2Si2 (R  Nd, Tb) with the tetragonal structure of the ThCr2Si2 type. CeRh2Si2 orders antiferromagnetically below 36 K with a wave vector k = [ 1 2 1 2 0] and magnetic moments parallel to the c-axis (m0) = 1.50 μ/Ce). The magnetic structure of TbRh2Si2 is antiferromagnetic (k = [001]) below TN = 94 K, the magnetic moments (8.5 μB/Tb at T = 15 K) are also parallel to the c-axis. NdRh2Si2 has the same magnetic structure below TN = 57 K, with m0 = 2.80 μB/Nd parallel to the c-axis. NdRu2Si2 exhibits a more complicated magnetic structure: below TN = 24 K it develops a sine-wave modulation (k = [0.130.130]) of the magnetic moments always parallel to the c-axis, with an amplitude Ak = 3.23 μB/Nd; a squaring of the magnetic structure occurs at about 15 K (m0 = 2.84 μB), and at T

Invar-like Behavior of Antiperovskite Mn3+xNi1–xN Compounds

Abstract: The antiperovskite Mn3+xNi1–xN compounds have been synthesized and characterized by a variety of experimental techniques. After Mn doping at the Ni site, both ferromagnetic characteristics and an Invar-like effect were observed in the antiferromagnetic host material. The observed Invar-like behavior was assumed to be related to the characteristic magnetic structure induced by the doping. Neutron diffraction results prove that the Mn doping stabilizes the special Γ5g antiferromagnetic phase with strong spin–lattice coupling that can be tuned to achieve Invar-like behavior. The magnetovolume effect (MVE) and significant correlation between spin and lattice were confirmed for the Γ5g magnetic phase by the first-principles calculations. Moreover, Mn 3d electrons were revealed to be the key factor for the MVE from the calculations. Our study presents a new mechanism for precisely controlling the zero thermal expansion of a single compound by achieving the special Γ5g magnetic phase of Mn atoms.