Magnetic field dependent tunneling magnetoresistance through a quantum well between ferromagnetic contacts

摘要

Spin-charge correlated dynamics is currently of great interest, because it allows to control the electric current and to obtain the large experimentally observed magnetic field dependent responses suitable for various practical applications. Resonant trap-assisted tunneling in heterostructures with ferromagnetic contacts explains the signal magnitude in three-terminal spin-injection experiments by the “spin blockade”: An electron cannot escape into the ferromagnetic contact, while the Coulomb blockade prevents a second electron to occupy the trap thus blocking the current. In the magnetic field the electron spin precesses and can escape into the contact, when the spin is parallel to the magnetization, and by this means the “spin blockade” is lifted. However, the non-trivial magnetoresistance can also be achieved without the Coulomb blockade. We investigate the magnetoresistance due to resonant tunneling through a quantum well separated from the two non-collinear ferromagnetic contacts by tunneling barriers. The linear part of the magnetoresistance is suitable for magnetic field sensing.