Spin transfer exchange torque in ferromagnet/ferromagnet structures made of half-metals with large exchange gaps

V Shablenko, YB Bazaliy - Physical Review B, 2023 - APS
V Shablenko, YB Bazaliy
Physical Review B, 2023APS
Spin torques in magnetic multilayers are produced by spin polarization P of ferromagnetic
(F) layers, and increase with growing P. The latter, however, cannot exceed the P= 1 value
found in half-metals. We study the P= 1 case to find what other parameters still influence
spin torques in this extreme limit. It is found that the ratio of the exchange gap to Fermi
energy strongly affects the properties of the torque. For large values of the gap, the
magnitude of exchange spin torque exhibits a sharp peak at very small misalignment angles …
Spin torques in magnetic multilayers are produced by spin polarization of ferromagnetic (F) layers, and increase with growing . The latter, however, cannot exceed the value found in half-metals. We study the case to find what other parameters still influence spin torques in this extreme limit. It is found that the ratio of the exchange gap to Fermi energy strongly affects the properties of the torque. For large values of the gap, the magnitude of exchange spin torque exhibits a sharp peak at very small misalignment angles between magnetizations. This behavior is found to be linked to a transition between Ohmic and tunneling transport regimes through the F/F boundary.
American Physical Society