Magnetic properties of Nd sub 7 Ni sub 3 single crystals

The magnetic properties of a hexagonal Th sub 7 Fe sub 3 -type Nd sub 7 Ni sub 3 single crystal have been investigated by measurements of the a.c. magnetic susceptibility, the magnetization and magnetic torque. There are three magnetic ordered phases at low temperature. At 4.2K, the compound shows a ferrimagnetic state with a very small resultant magnetization of 0.14 mu sub B /Nd along the c-axis. The metamagnetic transition takes place along the a- and b-axes at a magnetic field of approx13 kOe. As the temperature is increased, a spin reorientation takes place at 8.7K and the easy direction of the resultant magnetization deviates from the c-axis and lies in the c-plane which is perpendicular to the c-axis. At temperatures just < 8.7K, a very weak spontaneous magnetization of approx0.06 mu sub B /Nd is observed along the a- and b-axes. The magnetic state changes from ferrimagnetic to antiferromagnetic at 14K, and from antiferromagnetic to paramagnetic at 29K.