Magnetic ordering in Gd monopnictides: Indirect exchange versus superexchange interaction

Chun-gang Duan, University of Nebraska-Lincoln
Ildar F. Sabiryanov, University of Nebraska - Lincoln
W.N Mei, University of Nebraska - Lincoln
Peter A. Dowben, University of Nebraska-Lincoln
Sitaram Jaswal, University of Nebraska
Evgeny Y. Tsymbal, University of Nebraska-Lincoln

Document Type Article

Published Applied Physics Letters 88 (2006). Permission to use.

Abstract

The exchange interaction parameters of Gd monopnictides are deduced from fitting the total energies of different magnetic configurations to those computed within the Heisenberg model. The magnetic structures predicted by first-principles calculations as well as the Curie (Néel) temperatures obtained from Monte Carlo simulations are both in good agreement with experiments. A detailed analysis of the exchange parameters suggests that the Ruderman-Kittel-Kasuya-Yosida-type indirect exchange interactions and antiferromagnetic superexchange interactions coexist in these compounds. The magnetic order changes from ferromagnetic in GdN to antiferromagnetic in other Gd pnictides as a result of the increased ionic radius of a pnictide in the latter. ©2006 American Institute of Physics