Quantum Bicriticality in the Heavy-Fermion Metamagnet YbAgGe - Kölner UniversitätsPublikationsServer

Tokiwa, Y., Garst, M., Gegenwart, P., Bud'ko, S. L. and Canfield, P. C. (2013). Quantum Bicriticality in the Heavy-Fermion Metamagnet YbAgGe. Phys. Rev. Lett., 111 (11). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1079-7114

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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 T-BCP approximate to 0.3 K at a magnetic field of mu H-0(BCP) approximate to 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 T-BCP further to zero. Using high-resolution measurements of the magnetocaloric effect, we demonstrate that the magnetic Gruneisen parameter Gamma(H) indeed both changes sign and diverges as required for quantum criticality. Moreover, Gamma(H) displays a characteristic scaling behavior but only on the low-field side H <= H-BCP, indicating a pronounced asymmetry with respect to the critical field. We speculate that the small value of T-BCP is related to the geometric frustration of the Kondo lattice of YbAgGe.

Item Type:

Journal Article

Creators:

Creators	Email	ORCID	ORCID Put Code
Tokiwa, Y.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Garst, M.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Gegenwart, P.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Bud'ko, S. L.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED
Canfield, P. C.	UNSPECIFIED	UNSPECIFIED	UNSPECIFIED