Magnetic interactions in antiferromagnetic DyPO4(Zeeman spectra)

Abstract

Dysprosium phosphate (DyPO₄) orders antiferromagnetically at a Neel temperature of 3.4 K; the direction of the sublattice alignment is the c axis of the tetragonal unit cell. This ordered state arises from a combination of dipolar and exchange interaction and is well described by the Ising model for a highly anisotropic system of magnetic ions with ground state g values of g_c=19.5 g_a=g_a' approximately=0. Analysis of the high field Zeeman spectra below 20 K on the transition Z₁(⁶H₁₅2/) to G₁, which displays a pronounced quintet structure, enables an evaluation of the strength of the exchange interaction to be made. The result is confirmed by a direct determination of the interaction field from high field moment measurements at 0.5 K.