Exchange-driven spin relaxation in ferromagnet/oxide/semiconductor heterostructures

Abstract

We investigate electron spin relaxation in GaAs in the proximity of a Fe/MgO layer using spin-resolved optical pump-probe spectroscopy, revealing a strong dependence of the spin relaxation time on the strength of an exchange-driven hyperfine field. The temperature dependence of this effect reveals a strong correlation with carrier freeze out, implying that at low temperatures the free carrier spin lifetime is dominated by inhomogeneity in the local hyperfine field due to carrier localization. This result resolves a long-standing and contentious question of the origin of the spin relaxation in GaAs at low temperature when a magnetic field is present. Further, this improved fundamental understanding paves the way for future experiments exploring the time-dependent exchange interaction at the ferromagnet/semiconductor interface and its impact on spin dissipation and transport in the regime of dynamically-driven spin pumping.

24 pages, 7 figures

References in corpus (8)

• Spin Seebeck insulator
• Electrical Detection of Spin Transport in Lateral Ferromagnet-Semiconductor Devices
• Observation of the Spin-Seebeck Effect in a Ferromagnetic Semiconductor
• Theory of magnon-driven spin Seebeck effect
• Distinguishing Spin Relaxation Mechanisms in Organic Semiconductors
• Band structure of the epitaxial Fe/MgO/GaAs(001) tunnel junction studied by X-ray and ultraviolet photoelectron spectroscopy
• Spin Relaxation in Materials Lacking Coherent Charge Transport
• Anisotropic spin relaxation in $n$-GaAs from strong inhomogeneous hyperfine fields produced by the dynamical polarization of nuclei

Cited by in corpus (4)

• Evidence of Pure Spin-Current Generated by Spin Pumping in Interface Localized States in Hybrid Metal-Silicon-Metal Vertical Structures
• Driving a pure spin current from nuclear-polarization gradients
• Theory of oblique-field magnetoresistance from spin centers in three-terminal spintronic devices
• Tuning Spin Dynamics and Localization Near the Metal-Insulator Transition in Fe/GaAs heterostructures