Angular Dependent Magnetic Properties of CeCoIn$_{5}$ at Low Temperatures

The heavy-fermion compound CeCoIn$_{5}$ exhibits a superconducting transition at 2.3 K. As an unconventional superconductor, many unusual physical properties of the compound have been actively studied. In particular, evidence of a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state in this compound was reported first by Radovan and co-workers.$^{\dag }$ At the lowest temperature ($\sim $ 20 mK), the FFLO state of CeCoIn$_{5}$ was observed in fields between 10 and 11.7 T when the \textit{ab}-plane of the compound was placed parallel to the external magnetic field. In addition, at these low temperatures, the angular dependent peak effect was observed and interpreted as a crossover between Abrikosov and Josephson vortex lattices.$^{\ddag }$ Further experimental studies of the low temperature ($>$ 12 mK) magnetic properties of CeCoIn$_{5}$, performed in various sample orientations with respect to magnetic field will be presented. $^{\dag }$H.A. Radovan, et al., Nature \textbf{425} (2003) 51. $^{\ddag }$H.A. Radovan, et al., Philosophical Magazine \textbf{86} (2006) 3569.