High pressure neutron diffraction study of the magnetoresistive 1222-type ruthenocuprate, RuSr2Nd0.9Y0.2Ce0.9Cu2O10

The crystal structure of the 1222-type ruthenocuprate RuSr2Nd0.9Y0.2Ce0.9Cu2O10 has been studied by time-of-flight neutron diffraction at temperatures 100–160 K and pressures up to 5 GPa. The structure has tetragonal I4/mmm symmetry throughout (e.g. a = 3.8104(2) Å and c = 28.125(3) Å at 160 K and 5.1 GPa) with no significant distortions observed at the 140 K Ru spin ordering transition. The strongly bonded Cu–O and Ru–O network leads to a bulk modulus of 145 GPa which is high for layered cuprates, with a low anisotropy in the cell compressibility (kc/ka = 1.32). The Cu–O–Cu buckling angle and the tilting of the CuO5 square pyramids decreases with pressure, but the in-plane rotation of the RuO6 octahedra increases.