Crucial role of interfacial <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>s</mml:mi><mml:mtext>−</mml:mtext><mml:mi>d</mml:mi></mml:mrow></mml:math> exchange interaction in the temperature dependence of tunnel magnetoresistance
Keisuke Masuda, Terumasa Tadano, Yoshio Miura
Abstract
The tunnel magnetoresistance (TMR) is one of the most important spintronic phenomena but its reduction at finite temperature is a severe drawback for applications. Here, we reveal a crucial determinant of the drawback, that is, the $s\text{\ensuremath{-}}d$ exchange interaction between conduction $s$ and localized $d$ electrons at interfacial ferromagnetic layers. By calculating the temperature dependence of the TMR ratio in Fe/MgO/Fe(001), we show that the obtained TMR ratio significantly decreases with increasing temperature owing to the spin-flip scattering in the ${\mathrm{\ensuremath{\Delta}}}_{1}$ state induced by the $s\text{\ensuremath{-}}d$ exchange interaction. The material dependence of the coupling constant ${J}_{sd}$ is also discussed on the basis of a nonempirical method.