Theory of finite temperature Josephson transport through a ferromagnetic insulator.

Abstract: We predict an anomalous 0-π transition in Josephson junctions with a ferromagnetic-insulator (FI) barrier. Previously it wasfoundthattheground stateofsuch junctions alternates between0and π states when the thickness of FI is increasing by a single atomic layer. By solving the Bogoliubov de-Gennes equation and using the Furusaki-Tsukada formula, we show that similar 0-π transition canbe also inducedby increasing temperature T. Therefore the existence of π state can beexperimentally confirmedby simply observing the nonmonotonic T dependence of the Josephson critical current. [Copyright &y& Elsevier]