Green-function study of the J1-J2-Jc spin-exchange model for BaMn2As2
Department of Physics, Tsinghua University - 100084 Beijing, China
Received: 10 May 2012
Accepted: 11 June 2012
The magnetic properties of BaMn2As2 are investigated in the framework of the J1-J2-Jc Heisenberg model. Based on the equation-of-motion decoupling of Green's functions for the local moments, we derive the analytic formulas for the Néel temperature, staggered magnetization and the anisotropic spin susceptibility. By comparing the theoretical predictions with corresponding experimental data, the exchange couplings are estimated to be J1 ≈ 11.4 meV, J2/J1 ≈ 0.2, and Jc/J1 ≈ 0.1. The satisfactory fits of the measured susceptibility and magnetization by the theoretical results indicate that the Green-function method provides a rather good description of this local-moment model.
PACS: 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.) / 75.50.Ee – Antiferromagnetics / 75.30.Gw – Magnetic anisotropy
© EPLA, 2012