Multiple Transitions in Spin Glass Compound RbNiPO₄

Synthesis and characterisation of a new compound RbNiPO₄ was performed. Two transitions were observed in the magnetisation measurements in the low temperature regime around 20 K and 10 K. Magnetisation measurements also showed a hysterisis in the M vs. H at 2.1 K. This hysterisis showed a decrease with increasing temperatures, signifying ferromagnetic ordering at low temperatures. Curie - Weiss fit of the inverse susceptibility showed dominant antiferromagnetic interactions around 16 K. This suggests the ground state to be either canted antiferromagnetic or spin glass ordering. Spin glass/freezing state could be the reason for the splitting in zero- field cooling (ZFC) and field cooling (FC) magnetisation at around 10 K and 20 K. Further measurements such as heat capacity and AC magnetic susceptibility have to be done to find more information about the nature of these transitions.