Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 23: CE: Quantum-Critical Phenomena 2
TT 23.1: Vortrag
Dienstag, 15. März 2011, 10:30–10:45, HSZ 105
Electrical transport properties of single-crystal Nb1−yFe2+y — •Max Hirschberger1,2, William Duncan3, Andreas Neubauer2, Manuel Brando4, Christian Pfleiderer2, and Malte Grosche1 — 1Cavendish Laboratory, University of Cambridge, Cambridge, UK — 2Physik-Department E21, Technische Universität München, Garching, Germany — 3Department of Physics, Royal Holloway, University of London, Egham, UK — 4Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany
The Laves phase system Nb1−yFe2+y displays a marginal Fermi liquid breakdown close to the critical composition yc= −0.015 [1]. For y>−0.015 various bulk properties suggest the formation of hitherto unidentified electronic order at low temperatures akin a spin-density-wave (SDW) state. We have grown large single crystals of Nb1−yFe2+y by means of a bespoke image furnace. We present a study of the electrical transport properties of single-crystal Nb1−yFe2+y for three different compositions y and for a wide range of field orientations. All samples display strong anisotropy of the magnetoresistance between fields along the magnetically easy c-axis and the magnetically hard ab-plane. In a slightly iron-rich sample (y=0.006) we observed a pronounced peak in the magnetoresistance for magnetic fields perpendicular to the c-axis in a temperature range from 10 to 30 K. We discuss possible explanations for this behaviour, such as the emergence of complex magnetic textures near the border of ferromagnetic quantum criticality.
M. Brando et al, Phys. Rev. Lett. 101, 026401 (2008); D. Moroni-Klementowicz et al., Phys. Rev. B 79, 224410 (2009).