Enhancing spin-transfer torque through the proximity of quantum well states
Year: 2007
Type: article
Abstract: We predict that the spin-transfer, ${T}_{i,\ensuremath{\parallel}}$, and fieldlike, ${T}_{i,\ensuremath{\perp}}$, components of the local spin torque are dramatically enhanced in double-barrier magnetic tunnel junctions. The spin-mixing enhancement is due to the energetic proximity of majority and minority quantum well states (QWSs) of different quantum numbers within the bias window. The local-spin-torque enhancement is not associated with a corresponding enhancement of the spin-polarized currents. ${T}_{i,\ensuremath{\parallel}}$ exhibits a switch-on and switch-off steplike bias behavior when spin-polarized QWSs enter the bias window or exit the energy band, while ${T}_{i,\ensuremath{\perp}}$ changes sign between switch-on biases. The net ${T}_{\ensuremath{\perp}}$ exhibits an anomalous angular behavior due to the bias interplay of the bilinear and biquadratic effective exchange couplings.
Source: Physical Review B
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2056807231