Browsing by Author "Abreha, Merhawi"

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    Study of Ferromagnetism in Diluted Magnetic Semiconductor CAAS
    (Addis Ababa University, 2007-07) Abreha, Merhawi
    In the present study we study ferromagnetism of a transition free diluted magnetic semiconductor CaAs. Ferromagnetism in this curious material is due to the spin polarization of p-orbitals of the As atom. This mechanism is different from that of the CrAs in which Cr atoms possess magnetic moments [20, 23]. Ca atom does not have magnetic moments; its role is just to provide electrons with As atoms at the fcc site and to sustain crystal symmetry. The Curie temperature is estimated within an improvement over the mean-field approximation RKKY interaction for homogeneous systems with randomly distributed localized spins and is obtained to be approximately proportional to the spin concentration