Antiferromagnetic ordering on the frustrated fcc lattice in the intermetallic compound GdPtBi

Sergii Khmelevskyi

Center for Computational Material Science, Institute of Applied Physics, Vienna University of Technology, Makartvilla, Gusshausstrasse 25a, 1040 Vienna, Austria

(Received 29 May 2012; revised manuscript received 13 August 2012; published 24 September 2012)

Abstract

The type of antiferromagnetic magnetic order in the half-Heusler intermetallic compound GdPtBi, where the Gd atoms form a magnetically frustrated fcc lattice, has been investigated using exchange constants calculated from first principles within the framework of the Green’s function based magnetic force theorem. It is found that the degeneracy of the magnetic states on the fcc lattice with antiferromagnetic nearest neighbor interaction is removed by strong fourth-nearest neighbor interaction along the cube diagonal. We show that an antiferromagnetic ordering of so-called “third kind” occurs at low temperatures. The Monte Carlo simulations using our derived exchange constants predict an experimental Neel temperature ( ´ TN ) with good accuracy. The estimated temperature dependence of the correlation functions in the paramagnetic region exhibit a typical behavior for a frustrated system—a massive short-range order is retained for temperatures which are one order of magnitude higher than TN .

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