Takayuki Isono

Report Yo Machida1,*, Nayuta Matsumoto1, Takayuki Isono1, Kamran Behnia2,* 1Department of Physics, Gakushuin University, Tokyo 171-8588, Japan. 2Laboratoire Physique et Etude de Matériaux (CNRS-Sorbonne Université-ESPCI), PSL Research University, 75005 Paris, France. ↵*Corresponding author. Email: yo.machida{at}gakushuin.ac.jp (Y.M.); kamran.behnia{at}espci.fr (K.B.) See allHide authors and affiliations Science  17 Jan 2020: Vol. 367, Issue 6475, pp.

Abstract Superconductivity is one of the most intriguing topics in solid state physics. Generally, the superconducting Cooper pairs are broken by the Zeeman effect, which gives the so-called Pauli paramagnetic limit HPauli. However, when the superconductivity is in the clean limit and the orbital effect is strongly quenched, the Cooper pairs can survive even above HPauli, which is the so-called Fulde and Ferrell, and Larkin and Ovchinnikov (FFLO) phase.

The spin–lattice decoupling requires reconsideration of the data analysis in the heat-capacity measurement on κ-(BEDT-TTF) Cu (CN) . The heat capacity has been measured in a limited temperature and field region, T > 0.8 K and μ H < 8 T15. In this region, C is obtained by measuring the thermal relaxation in a long time scale, 10–100 s. This time scale is much longer than our lattice-heating result, 0.1–1 s, and even comparable to the spin-heating one,  0).