Pressure Dependence of the Lattice Distortion in Perovskite La_(0.5-x)Bi_xCa_(0.5)MnO_3(x=0.1,0.15,0.2)

摘要

The in situ behavior of distorted perovskite La_(0.5-x)Bi_xCa_(0.5)MnO_3(x=0.1,0.15,0.2) under high pressure has been studied by energy-dispersive X-ray diffraction in a diamond anvil cell.An abnormal change of the 202-040 d-spacing as-cribed to the disappearance of the distortion mode Q_2 in the MnO_6 octahedra is observed at 1.2,1.4,and 1.6 GPa,respectively,and it results in a reduction of the Jahn-Teller distorition commonly existing in the manganites.Effect of the unique 6s~2 long-pair character of the Bi~(3+) ion on the pressure dependence of the lattice distortion is discussed.