Abstract
Cubic spinel GeNi2O4 exhibits intriguing magnetic properties with two successive antiferromagnetic phase transitions (TN1≈12.1 and TN2≈11.4K) with the absence of any structural transition. We have performed detailed heat-capacity and magnetic measurements in different crystallographic orientations. A magnetic phase in the presence of the magnetic field (H≥4T) along the [111] direction is revealed, which is not observed when the magnetic field is applied along the [100] and [110] directions. High-field neutron powder-diffraction measurements confirm such a change in the magnetic phase, which could be ascribed to a spin reorientation in the presence of the magnetic field. A strong magnetic anisotropy and competing magnetic interactions play a crucial role in the complex magnetic behavior in this cubic system.
