The influence of the magnetic state on the thermal expansion in 1:2 rare earth intermetallic compounds

E. Gratz, A. Lindbaum

Publikation: Beitrag in FachzeitschriftArtikelBegutachtung

19 Zitate (Scopus)

Abstract

The attempt is made to demonstrate on some selected rare earth intermetallics the influence of the magnetic state on the thermal expansion. Using the X-ray powder diffraction method we investigated the thermal expansion of some selected non-magnetic compounds (YAl2, YNi2 and YCo2) and some magnetic RE (rare earth) - cobalt compounds (RCo2) in the temperature range from 4 up to 450 K. All these compounds crystallize in the C15-type structure (cubic Laves phase structure). By comparing the nonmagnetic Y-based compounds we could show that there is an enhanced contribution of the 3d electrons to the thermal expansion in YCo2. In the magnetic RCo2 compounds the induced 3d magnetism gives rise to large volume anomalies at the magnetic ordering temperature Tc. Below Tc there is in addition a distortion of the cubic unit cell due to the interaction of the magnetically ordered RE ions with the anisotropic crystal field. The thermal expansion of the orthorhombic TmCu2, GdCu2 and YCu2 compounds has also been investigated for comparison. The influence of the crystal field on the thermal expansion in TmCu2 in the paramagnetic range (TmCu2 orders magnetically at TN = 6.3 K) has been determined by comparing the thermal expansion of the nonmagnetic YCu2 with that of TmCu2. The data thus obtained are compared with a theoretical model. GdCu2, for which the influence of the crystal field can be neglected, has been investigated in order to study the influence of the exchange interaction in the magnetically ordered state (below 42 K).

OriginalspracheEnglisch
Seiten (von - bis)115-121
Seitenumfang7
FachzeitschriftJournal of Magnetism and Magnetic Materials
Jahrgang137
Ausgabenummer1-2
DOIs
PublikationsstatusVeröffentlicht - Okt. 1994
Extern publiziertJa

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