On Pulsed Magnetic Field Measurements of Enhanced Sommerfeld Constant \gamma and A-Coefficient around Metamagnetic Transition in UTe2

TL;DR

This paper provides a theoretical explanation for the differing behaviors of the A-coefficient and Sommerfeld constant  in UTe2 around the metamagnetic transition, emphasizing the role of measurement time scales and magnetic fluctuations.

Contribution

It introduces a theoretical framework that accounts for measurement time scale differences and magnetic fluctuations to explain experimental discrepancies in UTe2.

Findings

Time scale differences explain the symmetric and suppressed  behaviors.

Magnetic fluctuations persist after the first-order transition affecting measurements.

Properly considering probe time scales resolves the apparent paradox.

Abstract

It is discussed from theoretical viewpoint why the aspects of enhancements in the A-coefficient in the resistivity\cite{Knafo}and the Sommerfeld constant \gamma \cite{AtsushiMiyake,Imajo} observed in UTe2 around the metamagnetic transition at H=H_m are so different. In particular, the discussions are focused on the reason why the H dependence of the A-coefficient reported in Ref.\citen{Knafo} and \gamma reported in Ref.\citen{AtsushiMiyake}is almost symmetric around H=H_{\rm m}, while \gamma(H) at H\gsim H_m, reported in Ref.\citen{Imajo}, is considerably suppressed compared to that at H\lsim H_m. A key point to solve this seeming paradox is to take properly into account the difference in time scales of probes used in those measurements of pulsed magnetic field method with different time scales. Another crucial effect is the time dependent non-uniform magnetic fluctuations remaining in a certain period of time after the first-order metamagnetic transition has occurred. Indeed, the time scales of former measurements in Refs.\citen{Knafo,AtsushiMiyake} are far shorter than that of the latter one in Ref.\citen{Imajo}, which can solve the above paradox.