Effective quantum pseudospin-1/2 model for Yb pyrochlore oxides

Abstract

An effective quantum pseudospin-1/2 Hamiltonian for Yb2TM 2O7 (TM = Ti and Sn) is obtained in terms of the atomic Kramers ground doublet of the LS coupling and the crystalline electric field, which is almost described with Jz= ±1/2. It is calculated microscopically as the sum of Anderson's superexchange interaction and the magnetic dipole interaction. It is found that it shows a strong exchange anisotropy. © 2011 Published under licence by IOP Publishing Ltd.