Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 55: Poster II

MA 55.91: Poster

Freitag, 4. April 2014, 10:30–13:30, P2

Thin film synthesis of the semiconducting Heusler compound Fe2TiSi — •Markus Meinert¹, Manuel Patrice Geisler¹, Jan Michael Schmalhorst¹, Günter Reiss¹, and Elke Arenholz² — ¹Center for Spinelectronic Materials and Devices, Bielefeld University, Germany — ²Advanced Light Source, Berkeley, CA, USA

From band structure calculations, Fe₂TiSi is predicted to be a semiconductor with a narrow gap (about 0.3 eV) and a possible use for thermoelectric applications has been pointed out. [1]

We have synthesized L2₁ single-phase thin films of Fe₂TiSi on MgO substrates by DC and RF magnetron co-sputter deposition. The films have a resistivity of 1700 µ Ω cm at room temperature, reaching 4700 µ Ω cm at 2K. The carrier density is about 5 · 10²⁰cm⁻³ independent of temperature. These results are similar to earlier results on the pseudogap system Fe₂VAl. [2] The resistivity follows a logarithmic temperature dependence up to room temperature, which indicates Kondo scattering off magnetic impurities as the governing mechanism.

A band gap of about 0.4 eV is observed in optical absorption spectra and the general shape of the absorption and reflectance curves agrees with density functional theory calculations. Thus, Fe₂TiSi is in fact the first semiconducting full-Heusler compound reported to date.

[1] S. Yabuchi et al., Appl. Phys. Express 6, 025504 (2013). [2] H. Okamura et al., Phys. Rev. Lett. 84, 3674 (2000).