Pressure Study of Superconducting Oxypnictide LaFePO
  Electrical resistivity and magnetic susceptibility measurements under high pressure were performed on an iron-based superconductor LaFePO. A steep increase in superconducting transition temperature (Tc) of LaFePO with dTc/dP > 4 K/GPa to a maximum of 8.8 K for P = 0.8 GPa was observed. These results are similar to isocrystalline LaFeAsO1-xFx system reported previously. X-ray diffraction measurements were also performed under high pressure up to 10 GPa, where linear compressibility ka and kc are presented. 
K.Igawa, H.Okada, K.Arii, H.Takahashi, Y.Kamihara, M.Hirano, H.Hosono,   S.Nakano, T.Kikegawa