[25a-E201-1~11] 10.3 Spin devices, magnetic memories and storages

▲ [25a-E201-1] New physical origin of the temperature dependence of tunnel magnetoresistance: Crucial importance of interfacial s-d exchange interaction

〇Keisuke Masuda¹, Terumasa Tadano¹, Yoshio Miura¹ (1.NIMS)

Keywords:tunnel magnetoresistance, s-d exchange interaction

Achieving high tunnel magnetoresistance (TMR) ratios at room temperature is essential for magnetic tunnel junctions (MTJs). However, previous experiments on various MTJs have reported a significant decrease in the TMR ratio with increasing temperature. Here, we theoretically study the origin of this phenomenon in a typical Fe/MgO/Fe(001) MTJ. Our idea for explaining the sharp reduction of the TMR ratio is to consider the s-d exchange interaction in ferromagnetic Fe layers. We calculated the temperature dependence of the TMR ratio by applying the Kubo-Greenwood formula to the tight-binding model with the s-d exchange interaction. We found that the calculated TMR ratio significantly decreases with increasing temperature, consistent with experimental results.