Abstract
A neutron diffraction study has been made of the magnetic properties of the rare-earth-iron perovskites, NdFe, HoFe, and ErFe, at temperatures ranging from 955° to 1.25°K. The iron ions in each of these compounds undergo a transition to an antiferromagnetic configuration in which each moment has six oppositely directed moments at nearest neighbor distances. The Néel temperatures are 760°K, 700°K, and 620°K, respectively, for the compounds of Nd, Ho, and Er. The moment directions in HoFe and ErFe are parallel and antiparallel to the orthorhombic [100] direction at room temperature: at 43°K the moments are found to be in a () plane. In HoFe the iron-ion moments at 1.25°K are parallel to [001]; in Er at the same temperature they are parallel to [110]. The magnitudes of the ordered iron moments at temperature saturation are , , and Bohr magnetons in NdFe, HoFe, and ErFe, respectively. In the liquid helium temperature range, magnetic ordering transitions of the rare-earth ions in HoFe (K) and ErFe (K) are observed. The ion moments form a nearly ideal antiferromagnetic configuration in which a chain of parallel moments is surrounded by four chains of oppositely directed moments at nearest neighbor distances. In this compound the ion moments are parallel and antiparallel to [001] and at 1.25°K have a magnitude of 5.8 Bohr magnetons. In HoFe the ions are ordered in a distorted antiferromagnetic configuration in which, at 1.25°K, each moment with magnitude of 7.5 Bohr magnetons, makes an angle, in the (001) plane, of about 27° with the [010] direction so as to produce a net ferromagnetic moment of 3.4 Bohr magnetons per HoFe molecule parallel to [100].
- Received 16 October 1959
DOI:https://doi.org/10.1103/PhysRev.118.58
©1960 American Physical Society