2009 年 19 巻 2 号 p. 123-128
Electrical resistivity and magnetic susceptibility measurements under high pressure were performed on iron-based superconductor LaFePO and LaFeAsO1-xFx system. A steep increase in superconducting transition temperature (Tc) was observed for LaFePO and LaFeAsO1-xFx. Pressure-induced superconductivity was confirmed in undoped LaFeAsO and SrFe2As2 by electrical resistivity measurements under high pressure. X-ray diffraction measurements were also performed under high pressure up to 10 GPa for LaFePO, LaNiAsO and LaFeAsO1-xFx system, where the anisotropic decreases of the lattice constants were observed with applying pressure. Recent advance in the high pressure reserches for iron-based high Tc superconductors are also presented.