Kindai University Technical College, Japan
Title: The history of spin fluctuation theory in itinerant electron systems
Biography: Rikio Konno
The history of spin fluctuation theory in itinerant electron systems is overviewed. Doniach and Engelsburg developed spin fluctuation theory by using the random-phase approximation (R.P.A.) when they investigated magnetic specific heat. The magnetic susceptibility of their theory was the same as that of Wohlfarth. Murata and Doniach further developed spin fluctuation theory by RPA. Moriya and Kawabata successfully reproduced the Curie-Weiss law. Lonzarich, et al. and Moriya, et al. reproduced the T2-linear dependence of the magnetization at low temperature. However, their theory did not satisfy the magnetic scaling law. Takahashi resolved the problem by using the conserved spin local amplitude that is composed of the thermal component and the zero-point component. I discuss the recent results of the temperature dependence of the inverse magnetic susceptibility in itinerant electron systems.