Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 41: Poster III
MA 41.30: Poster
Donnerstag, 20. März 2025, 15:00–17:30, P3
Spin Seebeck effect in post-annealed NiFe2O4 thin films with varying lattice constants — •Fabian Meier, Julian Straßburger, Jan Biedinger, Tapas Samanta, Luana Caron, and Timo Kuschel — Bielefeld University, Germany
The longitudinal spin Seebeck effect (LSSE) in nickel ferrite (NFO) is a widely studied subject in the field of spin caloritronics [1]. Here, the dependence of the LSSE on the lattice constant is investigated in the ferrimagnetic insulator NFO. Two sample series have been fabricated by reactive DC magnetron sputter deposition [2], consisting of 45 nm thick NFO layers grown on MgAl2O4 substrates and post-annealed in an oxygen atmosphere at different temperatures ranging from 400 ∘C to 800 ∘C. Subsequently, the samples are capped by 3 nm of Pt for the spin current detection via the inverse spin Hall effect. The varying lattice constants of NFO, induced by the post-annealing, are analyzed with x-ray diffraction. The LSSE saturation voltage is determined by comparing the LSSE curves with magnetization measurements. Therewith, a linear contribution due to the ordinary Nernst effect in Pt is removed by adjusting the slope of the LSSE curve to match the magnetization curve in the saturation region. Afterwards, the averaged saturation values are determined as a function of the heat flux flowing through the sample. The spin Seebeck coefficient is calculated for each sample and the dependence on the post-annealing temperature, the lattice constants and the unit cell volume is examined.
[1] D. Meier et al., Nat. Commun. 6, 8211 (2015)
[2] C. Klewe et al., J. Appl. Phys. 115, 123903 (2014)
Keywords: Spin Seebeck Effect; Spin Caloritronics; Nickel ferrite; Ferrimagnetic insulators