Spin Seebeck effect has been investigated in Pt/ε-Fe2O3 bilayers. The ε-Fe2O3 thin layer with 40 − 70 nm thickness were deposited by a spin-coating method on Y:ZrO2(100) substrates. The prepared layers are highly oriented with the easy magnetic a-axis parallel to the film surface. The magnetic hysteresis loops measured at room temperature with magnetic field parallel to the layer exhibit coercive fields up to 11.6 kOe, which is so far the highest value measured for ε-Fe2O3 thin layer samples. The shape of the spin Seebeck hysteresis loops is similar to the shape of magnetization for single phase layers with coercive field around 10 kOe. In some prepared layers a small amount of secondary soft ferrimagnetic phase is revealed by a constricted shape of magnetization loops, in contrast to spin Seebeck loops, where no constriction is observed. A difference in encountered in the case of layers with a small amount (1 − 2 volume%) of secondary soft ferrimagnetic phase, which is revealed by a constricted shape of magnetization loops, in contrast to spin Seebeck loops, where no constriction is observed.

Spin Seebeck effect (SSE) has been investigated in thin films of two Y-hexagonal ferrites Ba2Zn2Fe12O22 (Zn2Y) and Ba2Co2Fe12O22 (Co2Y) deposited by a spin-coating method on SrTiO3(111) substrate. The selected hexagonal ferrites are both ferrimagnetic with similar magnetic moments at room temperature and both exhibit easy magnetization plane normal to c-axis. Despite that, SSE signal was only observed for Zn2Y, whereas no significant SSE signal was detected for Co2Y. We tentatively explain this different behavior by a presence of two different magnetic ions in Co2Y, whose random distribution over octahedral sites interferes the long range ordering and enhances the Gilbert damping constant. The temperature dependence of SSE for Zn2Y was measured and analyzed with regard to the heat flux and temperature gradient relevant to the SSE signal.

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