APS March Meeting 2011
Volume 56, Number 1
Monday–Friday, March 21–25, 2011;
Dallas, Texas
Abstract: D1.00003 : Universal Signatures of Metamagnetic Quantum Criticality
3:42 PM–4:18 PM
Preview Abstract
Author:
The continuous quest for quantum critical materials is inspired
by the
exotic phases and unusual phenomena that can be observed close to a
zero-temperature instability. An appealing realization of such a
critical
point is found in metamagnetic materials where the magnetization
shows a
finite step at a certain magnetic field that becomes more
pronounced at low
temperatures. The most striking advantages of this kind of quantum
criticality are that the critical point is i) symmetric in the
associated
thermodynamic phase diagram and not accompanied by a
symmetry-breaking
ordered phase and ii) the tuning parameter magnetic field $H$ can
be adjusted
continuously and makes a very detailed and comprehensive study of
this so
called quantum critical end-point (QCEP) possible.
In the presented talk the qualitative features of a field-driven
QCEP are
discussed, which result from very basic thermodynamic relations
and the two
general assumptions that i) the differential magnetic susceptibility
diverges at the critical field $H_{c}$ by definition and ii) the
QCEP has
Ising symmetry. We present real examples of metamagnetic systems,
where the
characteristics can be found experimentally. Particular emphasis
will be
placed on the well-known intermetallic material
CeRu$_{2}$Si$_{2}$. We argue
that a QCEP is approximately realized in this compound and
confirm our
claims by the combination of new high-resolution thermal expansion,
magnetostricion and specific heat results. Very similar behavior
was found
recently on the prominent material Sr$_{3}$Ru$_{2}$O$_{7}$ whose
metamagnetic quantum criticality is masked by the appearance of a
phase
proposed to be of nematic electronic nature.
We believe that our work will facilitate and promote the
experimental
identification of further metamagnetic systems for quantum
criticality in
the future.
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[1] \textit{Weickert et al}., Phys. Rev. B, \textbf{81}, 134438
(2010).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.D1.3