Spin current transport in EuIG thin films grown by pulsed laser deposition*

In this work, we investigate the spin transport in europium iron garnet (EuIG) thin films using spin Seebeck effect (SSE) and nonlocal transport. We grow high-quality epitaxial EuIG thin films on the substrates of (111)-oriented SGGG using the high vacuum pulsed laser deposition system followed by 750 degree ex-situ rapid thermal annealing. In nonlocal transport devices, the spin current is thermally injected from an AC current flowing in one platinum strip and detected by the other platinum strip located 3 um away using a lock-in amplifier at the double frequency via the inverse spin Hall effect. Our field and temperature dependent nonlocal reuslts suggest that it contains some additional contribution with the opposite sign to that of the Fe³⁺ ions in the low-field signals. The overall nonlocal responses are consistent with the SSE signals measured in the standard longitudinal geometry. This anomalous behavior may be attributed to the paramagnetic spin current contribution from the SGGG substrate. Our investigation future deeps the understanding of the spin transport in REIGs.