Theory and simulation of magnetism and spin transport in semiconductors

Abstract

<P>A THEORETICAL MODEL OF SPIN-TRANSPORT IN FERROMAGNET-SEMICONDUCTOR HYBRID STRUCTURES WHICH TAKES INTO ACCOUNT THE EFFECTS OF INTERFACE RESISTANCE HAS BEEN PRESENTED. SPIN-INJECTION EFFICIENCY AND MAGNETORESISTANCE WHICH ARE THE KEY PARAMETERS IN ANY SPINTRONICS DEVICE ARE STUDIED IN DETAIL. IT WAS FOUND THAT INTERFACIAL RESISTANCE WHICH IS DUE TO SPIN-SELECTIVE TUNNEL BARRIER AT BOTH THE INTERFACES OF HYBRID STRUCTURE PLAYS A CRUCIAL ROLE IN DETERMINING THE SPIN-INJECTION EFFICIENCY AND MAGNETORESISTANCE WHICH ARE THE PRINCIPAL REQUIREMENTS OF ANY SPINTRONICS DEVICE. TO ANALYZE THE SPIN-INJECTION EFFICIENCY IN THE STRUCTURE, A SELF-CONSISTENT MODEL HAS ALSO BEEN DEVELOPED WHICH CONSIDERS THE SPIN-TRANSPORT TO BE DIFFUSIVE IN THE BULK OF THE FERROMAGNET AND BALLISTIC WITHIN THE VICINITY OF INTERFACES. SPIN-DEPENDENT PROPERTIES ARE STUDIED AS A FUNCTION OF BARRIER-HEIGHTS AND IT WAS FOUND THAT SPIN-DEPENDENT INTERFACIAL RESISTANCE, SPIN-INJECTION EFFICIENCY AND MAGNETORESISTANCE INCRE