Possible unconventional superconductivity in iron-based layered compound   LaFePO: Study of heat capacity
  Heat capacity measurements were performed on recently discovered iron based layered superconductors, non doped LaFePO and fluorine doped LaFePO. A relatively large electronic heat capacity coefficient and a small normalized heat capacity jump at Tc = 3.3 K were observed in LaFePO. LaFePO0.94F0.06 had a smaller electronic heat capacity coefficient and a larger normalized heat capacity jump at Tc = 5.8 K. These values indicate that these compounds have strong electron electron correlation and magnetic spin fluctuation, which are the signatures of unconventional superconductivity mediated by spin fluctuation. 
Yoshimitsu Kohama, Yoichi Kamihara, Hitoshi Kawaji, Tooru Atake,   Masahiro Hirano and Hideo Hosono