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arXiv · 1507.01352

Spin-Hall magnetoresistance and spin Seebeck effect in spin-spiral and paramagnetic phases of multiferroic CoCr2O4 films

Aisha Aqeel·Nynke Vlietstra·Jeroen A. Heuver·Gerrit E. W. Bauer·Beatriz Noheda·Bart J. van Wees·Thomas T. M. Palstra
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Abstract

We report on the spin-Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) in multiferroic CoCr2O4 (CCO) spinel thin films with Pt contacts. We observe a large enhancement of both signals below the spin-spiral (Ts = 28 K) and the spin lock-in transitions (T_{lock_in} = 14 K). The SMR and SSE response in the spin lock-in phase are one order of magnitude larger than those observed at the ferrimagnetic transition temperature (Tc = 94 K), which indicates that the interaction between spins at the Pt|CCO interface is more efficient in the non-collinear magnetic state below Ts and T_{lock-in}. At T > Tc, magnetic field-induced SMR and SSE signals are observed, which can be explained by a high interface susceptibility. Our results show that the spin transport at the Pt|CCO interface is sensitive to the magnetic phases but cannot be explained solely by the bulk magnetization.

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Aisha Aqeel, Nynke Vlietstra, Jeroen A. Heuver, Gerrit E. W. Bauer, Beatriz Noheda, Bart J. van Wees, Thomas T. M. Palstra. 2015-07-06. Spin-Hall magnetoresistance and spin Seebeck effect in spin-spiral and paramagnetic phases of multiferroic CoCr2O4 films. https://doi.org/10.1103/physrevb.92.224410

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