Spin rotation, glassy state, and magnetization switching in RCrO_3 (R= La_(1-x)Pr_x, Gd, and Tm): Reinvestigation of magnetization reversal

摘要

We have reinvestigated the magnetization reversal in perovskites La1-xPrxCrO3, GdCrO3, and TmCrO3 and show that spin rotation or reorientation plays a key role in this property. The magnetization of La1-xPrxCrO3 as well as other chromites, including GdCrO3 and TmCrO3, indicates that the disappearance of magnetization reversal when x is increased from similar to 0.85 is caused by a flip of Pr3+ paramagnetic moments antiferromagnetically coupled with canted Cr3+ spins. This is due to a Zeeman energy of Pr3+ in analogy with a spin rotation in GdCrO3 and TmCrO3 below similar to 25 K, denoted as the spin reorientation transition. Magnetic susceptibility measurements point to either superparamagnetic or single-molecule-magnet-like glassy behavior in all three systems, which is likely linked to a rotation of the R3+-Cr3+ coupling, as seen from magnetocalorimetry (R = La1-xPrx, Gd, and Tm). We also present a characteristic magnetization switching by rotating the R3+ moments with the aid of large Zeeman energies.