Multiple regions of quantum criticality in YbAgGe

ORAL

Abstract

YbAgGe is a stoichiometric heavy fermion antiferromagnet that exhibits field-induced quantum criticality.~ We present and discuss thermal expansion and magnetostriction measurements that reveal a new field-induced state. On the low-field side of this state we find evidence for a first-order phase transition and suggest that YbAgGe may be close to a quantum critical end point at 4.5 T. On the high-field side we find evidence for a second-order phase transition suppressed to a quantum critical point near 7.2 T. We will discuss these results in light of global phase diagrams proposed for Kondo lattice systems. Work at Occidental College was supported by the National Science Foundation under DMR-1006118. Work at Ames Laboratory was supported by the Department of Energy, Basic Energy Sciences under Contract No. DE-AC02-07CH11358.

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Authors

  • G.M. Schmiedeshoff

    Occidental College

  • Sergey Bud'ko

    Ames Laboratory, Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Iowa State University, Iowa State University and Ames Lab., Iowa State University/Ames Lab, Iowa State University and Ames Laboratory US DOE, Ames Laboratory and Iowa State University, IA, USA, Ames Laboratory, Iowa State University

  • Paul Canfield

    Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University, Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Iowa State University, Iowa State University and Ames Lab., Iowa State University/Ames Lab, Iowa State University, Ames Laboratory, Ames Laboratory and Iowa State University, IA, USA, Ames Laboratory, Ames, IA 50011, U.S.A., Ames Laboratory, Iowa State University