Vortex lattice in Heavy-fermion CeCoIn5 probed by ac-calorimetry

J. KACMARCIK; P. PEDRAZZINI ; C. MARCENAT; Y. FASANO; V.F. CORREA; Z. PRIBULOVÁ; P. SAMUELY

Kosice

Conferencia; 16th Czech and Slovak Conference on Magnetism; 2016

Slovak Physical Society

The heavy-fermion CeCoIn5 presents a superconducting phase that can coexist with magnetic order when properly tuning different external parameters. This material is an interesting candidate to study the microscopic coupling giving rise to unconventional phenomena. One of its remarkable properties is the occurrence of vortex lattice structural changes as revealed by reciprocal-space imaging by small-angle neutron scattering at low temperatures [1]. The vortex lattice changes betweenhexagonal, rhombic and even square symmetries for certain ranges of temperatures and magnetic fields.We have performed a detailed thermodynamic study of CeCoIn5 by means of very sensitive ac-calorimetry. Continuous measurements while sweeping the temperature or magnetic field allowed us to inspect possible vortex-lattice structural phase transitions down to the sub-Kelvin temperature range. We will discuss our findings and compare them with the vortex phase diagram proposed from neutron data.This work was supported by the ERDF EU grant under contract No. ITMS26220120005 and the Argentina-Slovakia bilateral collaboration program Conicet-SAS.[1] A. Bianchi et al., Science 319 (2008) 177.