Anisotropy and spin reorientation of a single crystal of PrCo3Ni2

Magnetization measurements have been performed between 1.5 and 750 K on a single crystal of PrCo3Ni2 along the a, b, and c axes of the hexagonal structure. This compound orders magnetically below 635 K. Large anisotropy of the magnetic properties are observed. At low temperature, the b axis is the easy axis, whereas a progressive spin reorientation takes place between 155 and 185 K. This behavior has been confirmed by torque measurements. At higher temperature the c axis is the easy axis. Moreover, between 1.5 and 60 K, the magnetization process in the hard direction presents a smooth metamagneticlike behavior. Results are discussed in terms of competition between the anisotropies of 3d and 4f electrons.