Boosting room temperature tunnel magnetoresistance in hybrid magnetic tunnel junctions under electric bias

Spin-resolved electron symmetry filtering is a key mechanism behind gianttunneling magnetoresistance (TMR) in Fe/MgO/Fe and similar magnetictunnel junctions (MTJs), providing room temperature functionality in spinelectronics. However, the electron symmetry filtering breaks down underapplied bias, dramatically reducing the TMR above 0.5 V. This strongly ham-pers the application range of MTJs. To circumvent the problem, resonant tun-neling through quantum well states in thin layers has been used so far. Thismechanism, however, is mainly effective at low temperatures. Here, a funda-mentally different approach is demonstrated, providing a strong TMR boostunder applied bias in V/MgO/Fe/MgO/Fe/Co hybrids. This pathway uses spinorbit coupling (SOC) controlled interfacial states in vanadium, which contraryto the V(001) bulk states are allowed to tunnel to Fe(001) at low biases. Theexperimentally observed strong increase of TMR with bias is modeled usingtwo nonlinear resistances in series, with the low bias conductance of the first(V/MgO/Fe) element being boosted by the SOC-controlled interfacial states,while the conductance of the second (Fe/MgO/Fe) junctions are controlled bythe relative alignment of the ferromagnetic layers. These results pave a way tounexplored and fundamentally different spintronic device schemes, with tun-neling magnetoresistance uplifted under applied electric biasThe work in Madrid was supported by the Spanish Ministry of Science and Innovation (RTI2018-095303-B-C55) and the Consejería de Educación e Investigación de la Comunidad de Madrid(NANOMAGCOST-CM Ref. P2018/NMT-4321) grant

Efectos de proximidad en uniones superconductor/ferromagnético epitaxiales con interacción espín-órbita

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de Lectura: 18-05-2023Esta Tesis tiene embargado el acceso al texto completo hasta el 18-11-202