Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena
TT 6.69: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
Anisotropic length changes in Sr3Ru2O7 — •Christian Stingl and Philipp Gegenwart — I. Physikalisches Institut, Georg-August-Universität Göttingen
In the itinerant metamagnet Sr3Ru2O7, a first order metamagnetic transition is suppressed to a quantum critical end point (QCEP) at T=0 by applying a magnetic field µ0 Hc ≈ 8 T along the c-axis. Quantum critical behaviour is observed in thermal expansion and can be explained in terms of 2d ferromagnetic fluctuations.1
Below 1 K, a new phase with a strongly enhanced residual resistivity forms in the vicinity of the QCEP. When H has a small in-plane component, the resistivity becomes anisotropic, which is discussed in terms of formation of a symmetry-broken electronic nematic fluid organized into domains.2
Because of the strong magnetoelastic coupling, this reduction of symmetry could also be expected to lead to a distortion of the tetragonal lattice planes. The new phase could therefore be characterized by investigating thermal expansion and magnetostriction in the ab-plane perpendicular to the field.
For these measurements, we are testing a new miniaturized capacitive dilatometer, which can be rotated in the field and allows measuring length changes in various orientations relative to field and crystal axes.
This work is in collaboration with F. Weickert, R. Küchler, R.S. Perry and Y. Maeno.
[1] P. Gegenwart et al., PRL 96, 136402 (2006)
[2] R.A. Borzi et al., Science 315, 214-217 (2007)