Divergence of the Magnetic Gruneisen Ratio at the Field-Induced Quantum Critical Point in YbRh2Si2

被引：66

作者：

Tokiwa, Y. ^{[1
,2
]}

Radu, T. ^{[1
]}

Geibel, C. ^{[1
]}

Steglich, F. ^{[1
]}

Gegenwart, P. ^{[2
]}

机构：

[1] Max Planck Inst Chem Phys Solids, D-01187 Dresden, Germany

[2] Univ Gottingen, Inst Phys 1, D-37077 Gottingen, Germany

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 102卷 / 06期

关键词：

FERMI-LIQUID BEHAVIOR; HEAVY; TEMPERATURE; ELECTRON;

D O I：

10.1103/PhysRevLett.102.066401

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The heavy-fermion metal YbRh2Si2 is studied by low-temperature magnetization M(T) and specific-heat C(T) measurements at magnetic fields close to the quantum critical point (H-c=0.06 T, H perpendicular to c). Upon approaching the instability, dM/dT is more singular than C(T), leading to a divergence of the magnetic Gruneisen ratio Gamma(mag)=-(dM/dT)/C. Within the Fermi-liquid regime, Gamma(mag)=-G(r)(H-H-c(fit)) with G(r)=-0.30 +/- 0.01 and H-c(fit)=(0.065 +/- 0.005) T which is consistent with scaling behavior of the specific-heat coefficient in YbRh2(Si0.95Ge0.05)(2). The field dependence of dM/dT indicates an inflection point of the entropy as a function of magnetic field upon passing the line T-star(H) previously observed in Hall and thermodynamic measurements.

引用

页数：4

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