Campus Units

Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

9-13-2013

Journal or Book Title

Physical Review Letters

Volume

111

Issue

11

First Page

116401

DOI

10.1103/PhysRevLett.111.116401

Abstract

Bicritical points, at which two distinct symmetry-broken phases become simultaneously unstable, are typical for spin-flop metamagnetism. Interestingly, the heavy-fermion compound YbAgGe also possesses such a bicritical point (BCP) with a low temperature TBCP≈0.3  K at a magnetic field of μ0HBCP≈4.5  T. In its vicinity, YbAgGe exhibits anomalous behavior that we attribute to the influence of a quantum bicritical point that is close in parameter space yet can be reached by tuning TBCP further to zero. Using high-resolution measurements of the magnetocaloric effect, we demonstrate that the magnetic Grüneisen parameter ΓH indeed both changes sign and diverges as required for quantum criticality. Moreover, ΓH displays a characteristic scaling behavior but only on the low-field side H≲HBCP, indicating a pronounced asymmetry with respect to the critical field. We speculate that the small value of TBCP is related to the geometric frustration of the Kondo lattice of YbAgGe.

Comments

This article is published as Tokiwa, Y., M. Garst, P. Gegenwart, S. L. Bud’ko, and P. C. Canfield. "Quantum bicriticality in the heavy-fermion metamagnet YbAgGe." Physical Review Letters 111, no. 11 (2013): 116401. DOI: 10.1103/PhysRevLett.111.116401. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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