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HL: Fachverband Halbleiterphysik
HL 72: Focus Session: Functional Metal Oxides for Novel Applications and Devices III (joint session HL/DS)
HL 72.3: Vortrag
Donnerstag, 19. März 2020, 15:30–15:45, POT 81
Raman spectroscopy as a tool to determine the Néel temperature of NiO thin films in correlation with their structural characteristics — •Johannes Feldl, Melanie Budde, Carsten Tschammer, Oliver Bierwagen, and Manfred Ramsteiner — Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V., Hausvogteiplatz 5–7, 10117 Berlin, Germany
NiO is one of the most common natural antiferromagnetic (AF) oxides and a transparent p-type semiconductor making this material interesting for both, applications in the fields of spintronics and transparent-oxide electronics. One of the crucial magnetic parameters of AF materials is the Néel temperature (TN). For thin epitaxial films of NiO, TN will depend on the growth conditions and their resulting structural properties and is therefore expected to deviate from the value of 523 K for bulk NiO. Here, we utilize Raman spectroscopy to study the magnetic and structural properties of NiO thin films. The films are grown on MgO(100) substrates by plasma-assisted molecular beam epitaxy at different substrate temperatures. For the assessment of the structural properties, Raman scattering by optical phonons is analysed. Regarding the experimental determination of TN, we demonstrate a reliable approach by analyzing the temperature dependence of the two-magnon (2M) peak in the Raman spectra. The obtained TN values are below 480 K and are found to be correlated with the in-plane strain and the degree of lattice disorder in the NiO films.