Impurity-assisted tunneling magnetoresistance under weak magnetic field

Abstract

Injection of spins into semiconductors is essential for the integration of the spin functionality into conventional electronics. Insulating layers are often inserted between ferromagnetic metals and semiconductors for obtaining an efficient spin injection, and it is therefore crucial to distinguish between signatures of electrical spin injection and impurity-driven effects in the tunnel barrier. Here we demonstrate an impurity-assisted tunneling magnetoresistance effect in nonmagnetic-insulator-nonmagnetic and ferromagnetic-insulator-nonmagnetic tunnel barriers. In both cases, the effect reflects on/off switching of the tunneling current through impurity channels by the external magnetic field. The reported effect, which is universal for any impurity-assisted tunneling process, finally clarifies the controversy of a widely used technique that employs the same ferromagnetic electrode to inject and detect spin accumulation.

5 pages, 3 figures, Supplemental Material

References in corpus (3)

• Dissipationless Quantum Spin Current at Room Temperature
• Electronic measurement and control of spin transport in Silicon
• Inelastic electron tunneling spectroscopy of local "spin accumulation" devices

Cited by in corpus (8)

• An experimental demonstration of room-temperature spin transport in n-type Germanium epilayers
• Spin injection and detection up to room temperature in Heusler~alloy/$n$-GaAs spin valves
• Large spin accumulation voltages in epitaxial Mn5Ge3 contacts on Ge without oxide tunnel barrier
• Hanle-effect measurements of spin injection from Mn5Ge3C0.8/Al2O3-contacts into degenerately doped Ge channels on Si
• All-electric spin device operation using the Weyl semimetal, WTe${}_2$, at room temperature
• Suppressing spin relaxation in silicon
• Hot-electron effect in spin relaxation of electrically injected electrons in intrinsic Germanium
• The shape of the Hanle curve in spin-transport structures in the presence of the ac drive