Magnetic structure

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

Long-Wavelength Behavior, Impurity Scattering and Magnetic Excitations in a Marginal Fermi Liquid

Abstract: The marginal Fermi liquid hypothesis about the excitation spectrum of the high-temperature superconductors is supplemented to specify the long-wavelength behavior; it is shown that there are no anomalous renormalizations of the compressibility and the uniform paramagnetic susceptibility. Consideration of elastic scattering from impurities leads to the conclusion that as temperature is decreased, the scattering approaches the unitarity limit. We discuss the possibility that at T → 0, a marginal Fermi liquid is either a superconductor or an insulator. Predictions for the magnetic structure factor observable in neutron scattering consistent with the nuclear relaxation rate on copper and on oxygen are also given.

Magnetic Phase Diagram of the Triangular Lattice Antiferromagnet CuFe1-xAlxO2

Abstract: We have performed magnetic susceptibility, neutron diffraction and specific heat measurements on the triangular lattice antiferromagnet CuFe 1- x Al x O 2 for x ≤0.050. A magnetic phase diagram for temperature vs x was determined. The various magnetically ordered phases compete with each other on the x – T magnetic phase diagram, strongly suggesting that the quasi-Ising orderings are stabilized in CuFeO 2 with delicate balance of competing interactions. In the ground state for 0.014 < x < 0.030 [low-temperature (LT) phase], the magnetic structure consists of two magnetic modulations with slightly different wave numbers. Moreover, we observed the change in magnetic diffraction patterns in the LT phase, which corresponds to a crystallographic distortion from “hexagonal” to “orthorhombic”, suggesting that the Ising anisotropy in CuFeO 2 is closely related to the crystallographic distortion.

Long-range antiferromagnetic ordering in Bi2CuO4.

Abstract: The results of an investigation of ${\mathrm{Bi}}_{2}$${\mathrm{CuO}}_{4}$ using x-ray and neutron powder diffraction, dc magnetometry, and electron-spin resonance are presented. Simultaneous refinement of the room-temperature x-ray and neutron-diffraction data was used to obtain accurate cell parameters and atomic positions. Neutron-diffraction data at 13 and 300 K show that the appropriate space group is P4/ncc at both temperatures and reveal the appearance at the lower temperature of two magnetic peaks, which can be indexed as (100) and (210) reflections. While they are clearly indicative of long-range antiferromagnetic order, on the basis of these powder data alone one cannot determine the moment direction. However, on the assumption that the moments lie along the c axis, the copper magnetic moment is (0.56\ifmmode\pm\else\textpm\fi{}0.04)${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$. dc magnetometry was performed at temperatures from 1.66 to 400 K and fields ranging from 0.5 to 50 kOe. The magnetization showed no field saturation even at 1.66 K and 45 kOe. The susceptibility showed a maximum near 50.4 K with a Curie tail observed at low temperatures. Antiferromagnetic interactions dominated at all temperatures. The magnetic behavior is like that of a three-dimensional antiferromagnetic system. ESR experiments were done over the temperature range 4.3--300 K. For temperatures above 50 K, one broad line with g=2.09 was observed. The resonance field shifted to higher values for T37 K, with an eventual splitting of the line below 15 K. These ESR signals can be associated with antiferromagnetic resonance modes, consistent with an ordered antiferromagnetic phase.