Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 51: Magnetism Poster B
MA 51.56: Poster
Donnerstag, 4. April 2019, 15:00–18:00, Poster C
Enhancement of the spin Seebeck effect in lattice matched NiFe2O4 thin films — •Tobias Peters1, Ankur Rastogi2, Zhong Li2, Amit Vikam Singh2, Arunava Gupta2, Panagiota Bougiatioti1, Günter Reiss1, and Timo Kuschel1 — 1Center for Spinelectronic Materials and Devices, University of Bielefeld, Germany — 2MINT Center, University of Alabama, USA
We investigated the spin Seebeck effect (SSE) in Pt/NiFe2O4 films and studied the influence of thickness and film quality. Therefore, nickel ferrite (NFO) has been deposited in various thicknesses ranging from 50 nm to 1 µm on different substrates MgAl2O4 (MAO), MgGa2O4 (MGO) and CoGa2O4 (CGO) using pulsed laser deposition. These substrates present various lattice mismatches with respect to NFO ranging from 3.2 % for MAO to 0.2 % for CGO [1]. SSE measurements have been performed to investigate the influence of NFO-thickness and lattice mismatch, possibly accompanied by lattice defects and strain, on the magnon transport. For these measurements systematic errors could be eliminated via the normalization of the SSE driven electrical field to the applied heat flux instead to the temperature difference [2]. For the MGO- and CGO-samples we consistently found larger SSE signals compared to the MAO-samples, which could be connected to the lower lattice mismatch. Furthermore, magnon propagation lengths in the range of 100 nm to 1 µm have been determined, with the largest value attributed to NFO/MGO.
[1] A. V. Singh et al., Adv. Mater. 29, 1701222 (2017)
[2] A. Sola et al., Sci. Rep. 7, 46752 (2017)