Important Heat Contribution by Tunneling Spin Scattering in Magnetic Tunnel Junction

We investigated the heat contribution by tunneling spin scattering of magnetic tunnel junction in parallel (P) and antiparallel (AP) states using finite element simulation. It showed a maximum temperature increase of 23.2% from P to AP, which is even more significant than the heating asymmetry caused by different current directions. A remarkable enhancement of the temperature gradient was confirmed for contributing to the extra thermal spin-transfer torque to the free layer under a specific current direction. Both the contributions of enhanced temperature and temperature gradient should be the possible reasons for the asymmetry of the critical switching current density from P to AP and AP to P. We also extended the research to a double-barrier structure, clarifying its high performance from the aspect of heat generation. Our demonstration may offer efficient tunneling magnon excitation by using the tunneling spin scattering heat.