Neutronhyphen;diffraction measurements made on powder samples of TbIn3, TbPt3, and HoIn3show that all of these compounds exhibit antiferromagnetism below Neacute;el temperatures of 37thinsp;plusmn;thinsp;1deg;K, 20.5thinsp;plusmn;thinsp;0.5deg;K, and 11.5thinsp;plusmn;thinsp;0.5deg;K, respectively. The magnetic reflections from TbPt3can be indexed on a doubled chemical cell of cubic symmetry. A possible magnetic model consists of an arrangement where the Tb moments are aligned in opposite directions in adjacent (111) magnetic planes. The magnetic reflections from TbIn3and HoIn3can be indexed on a doubled chemical cell of tetragonal symmetry. An appropriate magnetic arrangement is one in which the rarehyphen;earth moments are aligned in opposite directions in adjacent (110) magnetic planes. For TbIn3the moment direction makes an angle of 10thinsp;plusmn;thinsp;5deg; with the unique orcaxis of the magnetic cell; for HoIn3the corresponding moment direction is 58thinsp;plusmn;thinsp;5deg;. The saturation ordered moment on the rarehyphen;earth atom sites in all three compounds is approximately 10percnt; less than the calculated or expected values. The magnetic structures are compared with predictions of the indirect exchange theory.
展开▼
