Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 53: Correlated Electrons: Heavy Fermions
TT 53.4: Vortrag
Donnerstag, 14. März 2013, 10:15–10:30, H19
The magnetic phase diagram of CeAu2Ge2 — •Felix Eilers1, Diego Zocco1, Chien-Lung Huang1,2, Veronika Fritsch2, Kai Grube1, and Hilbert v. Löhneysen1,2 — 1Karlsruher Institut für Technologie, Institut für Festkörperphysik — 2Karlsruher Institut für Technologie, Physikalisches Institut, Karlsruhe, Germany
CeAu2Ge2 hosts one of the lighter heavy-fermion systems located far on the magnetic side of the Doniach phase diagram. Being a strongly uniaxial antiferromagnet, its metamagnetic transition is of the spin-flip type. Recent neutron diffraction measurements [1] indicate several commensurate and incommensurate magnetic structures in the magnetically ordered state. In order to map out a detailed phase diagram we measured magnetostriction and thermal expansion on a CeAu2Ge2 single crystal. We found several phase transitions. The crystal under study has a Néel temperature of 9 K and a critical magnetic field around 3.4 T for B ∥ c [2]. The uppermost transition changes from continuous to discontinuous at temperatures below approximately 6 K. At temperatures below 0.5 K the phase-transition lines fan out and exhibit increased hysteresis. The Néel temperature of CeAu2Ge2 changes very little with hydrostatic pressure [3]. Using the Ehrenfest relation and the Clausius-Clapeyron relation we extracted the uniaxial pressure dependencies of the Néel temperature and the critical magnetic field.
[1] D. K. Singh et al., Physical Review B 86, 060405(R) (2012)
V. Fritsch et al., Physical Review B 84, 104446 (2011)
C. L. Huang et al., Physical Review B, in print (2012)