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MA: Fachverband Magnetismus
MA 3: Micro- and nanostructured Materials
MA 3.9: Talk
Monday, March 7, 2016, 11:45–12:00, H32
Electrical and thermal transport properties of FeCo thin films on SiN membrane based microcalorimeter — •Sasmita Srichandan, Matthias Kronseder, Christian Back, and Christoph Strunk — Institut für experimentelle und angewandte Physik, Universität Regensburg, Universitätstr. 31, 93053 Regensburg
We present the measurements of electrical resistivity, thermopower and thermal conductivity of 80nm thick films of FexCo1−x with compositions x = 0.3, 0.5, 0.64, 0.78 and 0.8 in a wide temperature range of 25 - 300 K. Our sample design consists of a rectangular SiN membrane structure suspended between two SiN islands covered with a ferromagnetic alloy film. Patterned thin wires of AuPd and Al constitute heaters and thermometers and assist in generating and measuring temperture difference between the two ends of the bridge respectively. Thermopower and thermal conductivity are measured at steady state while applying DC current to the heaters. All the measured transport coefficients exhibit strong dependence on temperature and the compositions of the alloys. At a given bath temperature the electrical resistivity increases monotonically with composition unlike typical binary alloys which show a maximum at x = 0.5 [1]. Deviation from Wiedemann Franz law is also observed. The measured transport coefficients are analysed to separate the contributions of different sub-systems such as the electrons, phonons and magnons.
[1] C. Y. Ho et.al,J. Phys. Chem. Ref. Data 12 183 (1983).