<i>Spin Seebeck Effect in insulating SrFeO<sub>3-</sub><sub>δ</sub> films</i>
POSTER
Abstract
SrFeO3 is a metal with cubic structure and is a helicoidal antiferromagnet (AF) at low temperatures (< 134 K) [1]. Recently, an anisotropic double q spin spiral and isotropic quadruple q spiral hosting a three-dimensional lattice of hedgehog singularities in SrFeO3 [2] was found suggesting a topologically non-trivial magnetic structure. Upon reduction, SrFeO3-δ becomes insulating while retaining long wavelength incommensurate AF order. In this work we measured the spin Seebeck effect (SSE)in SrFeO3-δ films synthesized by molecular beam epitaxy, and detected an SSE signal below 300 K. The measured SSE signal is enhanced below ~ 120 K, near the ordering temperature of incommensurate antiferromagnetism found in SrFeO3-δ bulk [3]. Control experiment were used to verify that the signal arises from a spin current originating in SrFeO3-δ and to rule out magnetic proximity effect. By comparing the second derivative of the SSE signal with respect to magnetic field and comparing to a Brillouin function, we find large deviations that suggest strong spin correlations in oxygen reduced SrFeO3-δ for temperatures below 120 K. Our work suggests SSE an effective way of probing magnetic correlations in non-ferromagnetic insulating films.
*This work was supported by the U.S. DOE, BES.
Presenters
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Deshun Hong
- Argonne National Laboratory
- Materials Science Division, Argonne National Laboratory