High-magnetic-field measurements of the magnetic moment of single crystals of yttrium orthoferrite were performed by torque and vibrating sample magnetometers. We investigated the magnetic states before and at the end of the field-induced spin reorientation and compared them with the theoretical predictions given by a macrospin model. The model describes the spin reorientation for low magnetic fields well. For high magnetic fields, the model predicts a 90${}^{\circ }$ spin rotation while the experiments indicate that the magnetic moment only rotates by 80${}^{\circ }$ for $H=74$ kOe and remains about 10${}^{\circ }$ out of a crystallographic axis, up to the highest measured field (280 kOe). This suggests that the initial magnetic interactions are altered by the strain induced by the spin reorientation, leading to a symmetry change.

• Received 30 November 2010

DOI:https://doi.org/10.1103/PhysRevB.84.104429