Magnetic field dependent specific heat and enhanced Wilson ratio in strongly correlated layered cobalt oxide

Abstract

We have investigated the low temperature specific heat properties as a function of magnetic field in the strongly correlated layered cobalt oxide [BiBa${}_{0.66}$K${}_{0.36}$O${}_2$]CoO${}_2$. These measurements reveal two kinds of magnetic field dependent contributions in qualitative agreement with the presence of a previously inferred magnetic Quantum Critical Point (QCP). First, the coefficient of the low temperature T${}^3$ behavior of the specific heat turns out to sizeably decrease near a magnetic field consistent with the critical value reported in a recent paper. In addition, a moderate but significant enhancement of the Sommerfeld coefficient is found in the vicinity of the QCP suggesting a slight increase of the electronic effective mass. This result contrasts with the divergent behavior of the previously reported Pauli susceptibility. Thus, a strongly enhanced Wilson ratio is deduced, suggesting efficient ferromagnetic fluctuations in the Fermi liquid regime which could explain the unusual magnetic field dependent specific heat. As a strong check, the high magnetic field Wilson ratio asymptotically recovers the universal limit of the local Fermi liquid against ferromagnetism.

arXiv comment5 pages, 4 figures

References in corpus (17)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Spin entropy as the likely source of enhanced thermopower in $\rm\bf Na_xCo_2O_4
• Universality and Critical Behavior at the Mott transition
• The ground state of Sr3Ru2O7 revisited; Fermi liquid close to a ferromagnetic instability
• Ferromagnetic quantum critical fluctuations in YbRh_2(Si_{0.95}Ge_{0.05})_2
• Quantum Critical Behavior and Possible Triplet Superconductivity in Electron Doped CoO2 Sheets
• Giant electron-electron scattering in the Fermi-liquid state of Na_0.7CoO_2
• Scaling behavior in thermoelectric misfit cobalt oxides
• Nonanalytic corrections to the specific heat of a three-dimensional Fermi liquid
• Strain induced pressure effect in pulsed laser deposited thin films of the strongly correlated oxide V2O3
• Interplay between magnetic properties and thermoelectricity in misfit and Na cobaltates
• Robustness of a local Fermi Liquid against Ferromagnetism and Phase Separation
• Magnetoresistance scaling in the layered cobaltate Ca3Co4O9
• Experimental study of the incoherent spectral weight in the photoemission spectra of the misfit cobaltate [Bi2Ba2O4][CoO2]2
• From quantum criticality to enhanced thermopower in strongly correlated layered cobalt oxide
• Spin fluctuations, magnetic long-range order and Fermi surface gapping in NaxCoO2
• Dual electronic states in thermoelectric cobalt oxide

Cited by in corpus (5)

• Strong magnetic instability in correlated metal Bi2Ir2O7
• Twisting of 2D kagomé sheets in layered intermetallics
• ω/T scaling of the optical conductivity in strongly correlated layered cobalt oxide
• Tomonaga-Luttinger liquid and quantum criticality in spin-1/2 antiferromagnetic Heisenberg chain C14H18CuN4O10 via Wilson ratio
• Signatures of a Majorana-Fermi surface in the Kitaev magnet Ag${}_3$LiIr${}_2$O${}_6$