Study Of Ferromagnetism In A New High Tc Ferromagnetic Semiconductor K2(s Ge) Without Transition Metal Element

In the present work we have studied the ferromagnetic properties of a high temperaturernmagnetic semiconductor K2S(Si=Ge) which is free from any transition metalrnelement. A model Hamiltonian taking into account, the exchange interaction of conductionrnelectrons with localized electrons coming from Si/Ge and the host is studiedrnusing quantum field theory formalism of Green functions and also using spin waverntheory to find expression for Curie temperature, TC, magnetic susceptibility, Â andrnspecific heat capacity of magnons excited. Tc,Â, and C are plotted with concentrationrnof dopants (Si/Ge). The direct proportionality relation of the Curie temperature, Tcrnand concentration, x of Ge in K2(S; Ge) have been shown. The reduced magnetizationrnvs the reduced temperature graph has been plotted. The plot shows convexrncurvature. The heat capacity vs temperature has also been plotted. The plot has gotrnparabolic curve nature for low concentration, x = 0:02 and become linear for highrnconcentration, x > 0:08, which are in good agreement with available experiments.rnWe also plotted the graph for the reciprocal of the susceptibility versus temperaturerndifference. As can be seen from the graph the material is in its ferromagnetic staternfor T < 299:9K. And (1=Â) = 0 at T = TC = 300K, and the graph is straight linernafter T = 300K. Which shows the material leaves its ferromagnetic state for T = TC.rnWhich are in good agreement with available experiments

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