On the Possible Mechanisms for Temperature-Induced Ferromagnetism

Abstract

Possible occurrence of weak itinerant ferromagnetism in a certain temperature interval, with a lower bound at finite temperature, in otherwise paramagnetic metals is studied taking account of the effect of exchange-enhanced spin fluctuations. Within the weakly ferromagnetic regime this phenomenon is shown to be hardly possible; negative mode-mode couplings among the long wavelength modes of spin fluctuations do not lead to this phenomenon. Other possible mechanisms for this phenomenon are discussed in relation to the magnetism of Y 2 Ni 7 , where such a behavior was reported.