Specific heat measurements of the high-temperature magnetic superconductor RbEuFe<sub>4</sub>As<sub>4</sub>
ORAL
Abstract
We report specific heat measurements on the newly discovered magnetic superconductor RbEuFe4As4. We investigated the superconducting transition at Tc = 38K and extracted the phase boundary for in and out of plane magnetic fields and obtained an anisotropy ratio of 1.8. At small fields near the magnetic transition temperature Tm ~ 14.9K, we resolved a cusp-like behavior in the temperature dependence of the specific heat curve that shifts to lower temperatures for fields along the c-axis and a broad shoulder that shifts to higher temperatures for in-plane fields. We can reproduce our measured calorimetry data quantitatively by Monte-Carlo simulations of an anisotropic easy-plane 2D Heisenberg model that suggests that the cusp in specific heat is due to a BKT transition and the high temperature hump at higher fields marks a crossover from a paramagnetically disordered to an ordered state.
*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. K. W. and R. W. acknowledge support from the Swiss National Science Foundation through an Early Postdoc Mobility fellowship.
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Presenters
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Wai-Kwong Kwok
- Argonne National Laboratory
- Materials Science Division, Argonne National Laboratory
- Material Science Division, Argonne National Laboratory
- Materials Sciences Division, Argonne National Laboratory
- Argonne National Lab