The magnetic structure of the compounds UOS, ß-CoSO4, YCO5, and HoCO5 is briefly described.
UOS is antiferromagnetic. The Néel temperature is Tn=55°K. The magnetic cell is doubled in the c direction with a ++ - - sequence of U moments along c. The apparent spin is S∼1. The negative interaction corresponds to U-O-U links.
In ß-CoSO4 (high-temperature modification, space group Pbnm), Co atoms are in 000, 00½, ½½½, ½½0. Here three different antiferromagnetic spin modes, mutually perpendicular, Ax(+ - - +), Gy(+-+-), and Cz(++ - - ), in the Wollan-Koehler notation, are coupled. Direction cosines are 0.71, 0.50, and 0.50, respectively. The Co moment is about 3,84 µB at 4.2°K. A field-induced spin flip to the configuration Fx, Cy, Gz is predicted.
YCO5 is ferromagnetic at room temperature with a moment value of Co practically equal to that of metallic Co and moment direction along c, which is conserved down to 4.2°K.
In HoCO5 the moment of Ho is opposite to those of the Co atoms. When cooling from room to liquid helium temperature, the direction of easy magnetization changes from near c to a direction in the basal plane and the Ho moment increases from 4 to about 9 µB. The compensation temperature is 70°K.
R. Ballestracci et al., "Magnetic Structure Investigations at the Nuclear Center," Journal of Applied Physics, vol. 34, no. 4 (Part 2), pp. 1333-1334, American Institute of Physics (AIP), Apr 1963.
The definitive version is available at https://doi.org/10.1063/1.1729495
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© 1963 American Institute of Physics (AIP), All rights reserved.
01 Apr 1963