Unusual critical behavior of Griffiths ferromagnet Ho2NiMnO6 at magnetic phase transition

Abstract

The critical behavior at the ferromagnetic to paramagnetic phase transition of a Griffiths ferromagnet, Ho2NiMnO6, is studied using modified Arrott plot, Kouvel–Fisher, and critical isotherm analysis. Here, we report a second-order phase transition and conclude from the estimated critical exponents that it is unusual and do not belong to conventional universality classes. However, they obey scaling relationships, which indicates the renormalization of interactions around the phase transition temperature. The presence of Griffiths phase in the system accounts for the unusual critical exponents observed.