Magnetic interactions in gadolinium orthochromite, GdCrO₃

Abstract

The magnetic properties of the distorted perovskite GdCrO3 have been investigated by magnetic moment measurements in the temperature range below 100K and specific heat measurements below 10K. Measurements show that the canting of the Cr3+ ions from a simple antiferromagnetic alignment is due to antisymmetric exchange coupling between Cr ions. The value of the weak ferromagnetic moment Fz is 400 emu mol-1. The interaction between the Cr3+ and Gd3+ ions produces an effective field at the Gd sites of 5.5 kOe, acting in the opposite direction to Fz. At a temperature of approximately 7K the Cr-Gd interaction is sufficient to cause the Cr system to undergo a spontaneous spin reorientation from a GxFz to a GzFx mod. At 2.3K the interaction between the Gd3+ ions is sufficient to bring about a co-operative transition to an antiferromagnetic state.