Tunneling magnetothermopower in magnetic tunnel junctions

Abstract

Thermally induced spin-dependent transport across magnetic tunnel junctions (MTJs) is theoretically investigated. We analyze the thermal analog of Slonczewski's model (as well as its limiting case-Julliere's model) of tunneling magnetoresistance and obtain analytical expressions for the junction thermopower and the tunneling magnetothermopower (TMT). The analytical model is tested numerically for the special case of an Al 2 O 3 -based MTJ, for which we analyze the dependence of the thermopower and TMT on the relative magnetization orientations, as well as on the barrier height and thickness. We show that at a certain barrier height TMT vanishes, separating the region of positive and negative TMT. As its electrical prototype, this thermal spin transport model should serve as a phenomenological benchmark for analyzing experimental and first-principles calculations of thermopower in magnetic tunnel junctions. The analytical expressions can be used as a first estimate of the magnetothermopower of the junctions using ab initio band structure data of the junction ferromagnets.

Anisotropic optical properties of Fe/GaAs(001) nanolayers from first principles

“…Combining Eqs. (6)- (8), (14)- (16), (18), (20), (21), (24), and (25) (3), allows us to determine the energy-dependent AP-MOKE rotation and ellipticity for an incoming beam at normal incidence whose direction of linear polarization in the xy plane is rotated by ϕ with respect to the x axis.…”

Comparison of the magneto-Peltier and magneto-Seebeck effects in magnetic tunnel junctions

“…Many interesting physical phenomena were discovered such as the spin (-dependent) Seebeck effect in magnetic metal [8], magnetic semiconductor [9] and magnetic insulator [10]. Particularly, in spin tunneling devices, the magneto-Seebeck effect was theoretically studied [11][12][13][14] and experimentally observed [15][16][17][18][19] in MTJs, where the Seebeck coefficient of the junction can be varied by changing the magnetic configuration. More recently, the spin (-dependent) Peltier effect that is driven by spin (polarized) currents has been experimentally observed in metallic [20,21] and insulating ferromagnets [22], which are shown to obey the Thomson-Onsager reciprocity relation [23][24][25] to the spin (-dependent) Seebeck effect.…”

Tunneling anisotropic thermopower and Seebeck effects in magnetic tunnel junctions

“…investigation of the tunneling magnetothermopower in MTJs with two magnetic electrodes [49]. We shall next discuss the Hamiltonian for the system and, in the following, the differences between both models will be indicated in Table II.…”