Spin-transfer torque in magnetic tunnel junctions

Kalitsov, A; Chshiev, M; Theodonis, I; Kioussis, N; Butler, WH

dc.contributor.author	Kalitsov, A	en
dc.contributor.author	Chshiev, M	en
dc.contributor.author	Theodonis, I	en
dc.contributor.author	Kioussis, N	en
dc.contributor.author	Butler, WH	en
dc.date.accessioned	2014-03-01T01:31:58Z
dc.date.available	2014-03-01T01:31:58Z
dc.date.issued	2009	en
dc.identifier.issn	1098-0121	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19993
dc.subject	antiferromagnetism	en
dc.subject	electronic structure	en
dc.subject	ferromagnetism	en
dc.subject	magnetic tunnelling	en
dc.subject	magnetisation	en
dc.subject	magnetoresistance	en
dc.subject	tight-binding calculations	en
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	VOLTAGE-DEPENDENCE	en
dc.subject.other	ROOM-TEMPERATURE	en
dc.subject.other	PHASE-LOCKING	en
dc.subject.other	MAGNETORESISTANCE	en
dc.subject.other	DRIVEN	en
dc.subject.other	CONDUCTANCE	en
dc.subject.other	INVERSION	en
dc.subject.other	OXIDATION	en
dc.subject.other	EMISSION	en
dc.subject.other	BARRIERS	en
dc.title	Spin-transfer torque in magnetic tunnel junctions	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevB.79.174416	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevB.79.174416	en
heal.identifier.secondary	174416	en
heal.language	English	en
heal.publicationDate	2009	en
heal.abstract	We present a theoretical study of the spin-transfer torque vector and the tunneling magnetoresistance (TMR) for symmetric magnetic tunnel junctions (MTJ) using the single-band tight-binding model and the nonequilibrium Keldysh formalism. We provide a comprehensive analysis of the effect of band filling and exchange splitting of the FM leads on the bias behavior of the spin-transfer component, T-parallel to, in the plane containing the magnetizations of the two magnetic layers, and the fieldlike component, T-perpendicular to, perpendicular to this plane. We demonstrate that both components of the spin torque and the TMR can exhibit a wide range of interesting and unusual bias behavior. We show that T-parallel to(V) satisfies an expression involving the difference in spin currents between the ferromagnetic (FM) and antiferromagnetic (AF) configurations, which is general and independent of the details of the electronic structure. The spin current for the FM (AF) alignment is shown to have a linear (quadratic) bias dependence, whose origin lies in the symmetric (asymmetric) nature of the barrier. On the other hand, the bias dependence of T-perpendicular to is quadratic with d(2)T(perpendicular to)/dV(2)< 0, and it can change sign at finite bias. Finally, we show that the exchange splitting and band filling have a large effect on the bias dependence of the TMR.	en
heal.publisher	AMER PHYSICAL SOC	en
heal.journalName	Physical Review B - Condensed Matter and Materials Physics	en
dc.identifier.doi	10.1103/PhysRevB.79.174416	en
dc.identifier.isi	ISI:000266501100069	en
dc.identifier.volume	79	en
dc.identifier.issue	17	en