Regensburg 2019 – wissenschaftliches Programm
HL 45.53: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Structural and magnetic properties of MBE-grown NiO thin films studied by Raman spectroscopy — •Johannes Feldl, Melanie Budde, Carsten Tschammer, Oliver Bierwagen, and Manfred Ramsteiner — Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institute of the Forschungsverbund Berlin e. V., Hausvogteiplatz 5–7, 10117 Berlin, Germany
NiO is an antiferromagnetic oxide and a transparent p-type semiconductor making this material interesting for applications in the fields of spintronics and transparent electronics. The physical properties of NiO thin films often depend on the strain state and existence of grain boundaries. Using Raman spectroscopy, the structural and magnetic properties of NiO films grown on MgO(100) by plasma-assisted molecular beam epitaxy at different substrate temperatures were investigated. The structural properties of the NiO films are studied by the analysis of second-order phonon scattering. The respective frequencies reflect the strain state in the NiO films. In addition, the phonon confinement due to the formation of grains and the diffusion of Mg into the NiO films possibly affect the actual values of the phonon frequencies. The magnetic characteristics of the NiO films is investigated by temperature-dependent second-order Raman scattering originating from magnons. As a result, a clear dependence of the Néel temperature on the growth conditions is found. The analysis of our results allows for the identification of structural effects on the antiferromagnetic superexchange interaction in the NiO films.