Effect of Fe atomic layers at the ferromagnet-semiconductor interface on temperature-dependent spin transport in semiconductors

Using artificially controlled ferromagnet (FM)-semiconductor (SC) interfaces, we study the decay of the nonlocal spin signals with increasing temperature in SC-based lateral spin-valve devices. When more than five atomic layers of Fe are inserted at the FM/SC interfaces, the temperature-dependent spin injection/detection efficiency (P-inj/det) can be interpreted in terms of the T-3/2 law, meaning a model of the thermally excited spin waves in the FM electrodes. For the FM/SC interfaces with the insufficient insertion of Fe atomic layers, on the other hand, the decay of P-inj/det is more rapid than the T-3/2 curve. Using magneto-optical Kerr effect measurements, we find that more than five atomic layers of Fe inserted between FM and SC enable us to enhance the ferromagnetic nature of the FM/SC heterointerfaces. Thus, the ferromagnetism in the ultra-thin FM layer just on top of SC is strongly related to the temperature-dependent nonlocal spin transport in SCbased lateral spin-valve devices. We propose that the sufficient ferromagnetism near the FM/SC interface is essential for high-performance FM-SC hybrid devices above room temperature. Published under an exclusive license by AIP Publishing.

Automated summary

The study investigates the impact of inserting different numbers of Fe layers at the FM/SC interface in lateral spin-valve devices. When more than five layers of Fe are inserted, the efficiency decay with temperature can be explained by the T-3/2 law, while with insufficient Fe layers the decay is faster.