Magnetic interactions in gadolinium orthochromite, GdCrO 3

The magnetic properties of the distorted perovskite GdCrO 3 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 Cr 3+ ions from a simple antiferromagnetic alignment is due to antisymmetric exchange coupling between Cr ions. The value of the weak ferromagnetic moment F z is 400 emu mol -1 . The interaction between the Cr 3+ and Gd 3+ ions produces an effective field at the Gd sites of 5.5 kOe, acting in the opposite direction to F z . 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 G x F z to a G z F x mod. At 2.3K the interaction between the Gd 3+ ions is sufficient to bring about a co-operative transition to an antiferromagnetic state.