Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 27: CE: Poster Session
TT 27.19: Poster
Wednesday, March 24, 2010, 14:00–18:00, Poster D1
Anisotropy in the microwave conductivity of UNi2Al3 — •Katrin Steinberg1, Marc Scheffler1, Martin Dressel1, and Martin Jourdan2 — 11. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany — 2Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany
In the heavy-fermion compound UNi2Al3, the free charge carriers show an enhanced effective mass at low temperatures due to electronic correlations. This mass enhancement and a strongly enhanced scattering time can be observed in the microwave conductivity spectrum. The frequency dependent complex conductivity shows a Drude roll-off at a few GHz. From directionally dependent dc studies it is known that UNi2Al3 exhibits a pronounced transport anisotropy at low temperatures. To resolve whether the conductivity at microwave frequencies is anisotropic as well, we have prepared strip-shaped thin-film samples of UNi2Al3 and measured their conductivity in a broadband microwave Corbino spectrometer with the current parallel to the a-axis or to the c-axis of the hexagonal crystal structure. We present the frequency- and temperature-dependent microwave conductivity (45 MHz to 40 GHz and 1 K to 300 K, respectively) of UNi2Al3. The conductivity spectra exhibit clear Drude roll-offs in both crystallographic directions. They are anisotropic, in consistence with the dc transport. From the measured spectra we obtain the effective mass and scattering rate for both crystal axes and we study their temperature dependence.