APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session L40: Invited Session: New Horizons for Magnetism and Competing Phases in Heavy Fermions
8:00 AM–11:00 AM,
Wednesday, March 5, 2014
Room: Mile High Ballroom 2B-3B
Sponsoring
Unit:
DCMP
Chair: Paul Canfield, Ames Laboratory
Abstract ID: BAPS.2014.MAR.L40.5
Abstract: L40.00005 : Tricritical point and wing structure in the phase diagram of UGe$_2$
10:24 AM–11:00 AM
Preview Abstract
Abstract
Author:
Valentin Taufour
(Critical Material Institute, Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.)
Among the numerous reports on quantum criticality, studies on ferromagnets are less common than studies on antiferromagnetic compounds. This is surprising since the paramagnetic to ferromagnetic transition is a textbook example of second order transition and there are several examples where the ferromagnetic transition can be tuned to zero temperature by applied pressure, chemical doping or magnetic field. However, it seems that the transition becomes first order at a tricritical point before being fully suppressed, changing the quantum critical point to a first order quantum phase transition. I will present the case of the superconducting ferromagnet UGe$_2$. In this material, we experimentally located the tricritical point in the temperature-pressure phase diagram. By applying magnetic field, the critical end point, which corresponds to the tricritical point at zero field, can be located leading to a wing-structure in the temperature-pressure-magnetic field phase diagram. The suppression of the critical end point to zero temperature leads to a new kind of quantum criticality: a quantum critical end point. The case of UGe$_2$ will be compared with other ferromagnets, in particular LaCr$_{1-x}$V$_x$Ge$_3$.
The work on UGe$_2$ was performed at CEA Grenoble, France with D. Aoki, G. Knebel, H. Kotegawa, L. Malone, I. Sheikin and J. Flouquet. The work on other compounds is performed at my present institution Ames Laboratory, Iowa State University, Ames, Iowa, U.S.A. with U. Kaluarachchi, X. Lin, S. K. Kim, S. L Bud'ko and P. C. Canfield supported by AFOSR-MURI grant FA9550-09-1-0603.
\\[4pt]
[1] Tricritical point and wing structure in the itinerant ferromagnet UGe$_2$ V. Taufour, D. Aoki, G. Knebel, and J. Flouquet Physical Review Letters 105, 217201 (2010)
\\[0pt]
[2] Evolution toward Quantum Critical End Point in UGe$_2$ H. Kotegawa, V. Taufour, D. Aoki, G. Knebel, and J. Flouquet Journal of the Physical Society of Japan Vol. 80, No. 8, 083703 (2011)
\\[0pt]
[3] Ferromagnetic Quantum Critical Endpoint in UCoAl D. Aoki, T. Combier, V. Taufour, T. D. Matsuda, G. Knebel, H. Kotegawa, and J. Flouquet Journal of the Physical Society of Japan Vol. 80, No. 9, 094711 (2011)
\\[0pt]
[4] Suppression of ferromagnetism in the LaV$_x$Cr$_{1-x}$Ge$_3$ system Lin, Xiao and Taufour, Valentin and Bud'ko, Sergey L. and Canfield, Paul C. Phys. Rev. B 88 094405 (2013)
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.L40.5