Effect of the magnetic domain structure in the ferromagnetic contact on spin accumulation in silicon

TL;DR

This study demonstrates that the magnetic domain structure in ferromagnetic contacts significantly influences spin accumulation signals in silicon, affecting measurements and interpretations in spintronics experiments.

Contribution

It reveals the impact of magnetic domain walls in ferromagnetic contacts on spin signals and highlights the importance of considering domain structures in spin accumulation measurements.

Findings

Domain walls reduce spin accumulation signals.

Domain structures affect spin lifetime and bias dependence.

Ignoring domain effects causes errors in measurements.

Abstract

We show a marked effect of the magnetic domain structure in an epitaxial CoFe contact on the spin accumulation signals in Si detected by three-terminal Hanle-effect measurements. Clear reduction in the spin accumulation signals can be seen by introducing the domain walls in the CoFe contact, caused by the lateral spin transport in the Si channel. The domain walls in the CoFe contact largely affect the spin lifetime and bias-current dependence of the spin signals. These results indicate that the estimation of the spin related properties without considering the domain structure in the contact causes non-negligible errors in the three-terminal Hanle-effect measurements.