Detection of high-field superconducting phase in CeCoIn$_5$ with   magnetic susceptibility
  We measure the ac susceptibility of single-crystal CeCoIn5 in dc field parallel to the c axis and find further evidence for a high-field phase transition within the superconducting phase in this orientation. We apply up to 2.3 kbar uniaxial pressure along the c axis and discuss the pressure dependence of the high-field phase. We also report the behavior of Hc2 under uniaxial pressure for field along c. 
S. D. Johnson, R. J. Zieve, J. C. Cooley
cond-mat.supr-con