NMR investigation of superconductivity and Antiferromagnetism in CaFe2As2 under pressure

Phys Rev Lett. 2009 Jun 5;102(22):227601. doi: 10.1103/PhysRevLett.102.227601. Epub 2009 Jun 3.

Abstract

We report 75As NMR measurements in CaFe2As2, made under applied pressures up to 0.83 GPa produced by a standard clamp pressure cell. Our data reveal phase segregation of paramagnetic and antiferromagnetic (AFM) phases over a range of pressures, with the AFM phase more than 90% dominant at low temperatures. In situ rf susceptibility measurements indicate the presence of superconductivity. 75As spin-lattice relaxation experiments indicate that the 75As nuclei sample the superconductivity while in the magnetically ordered environment.