Studies on Li-doped Ca_0·85Sr_0·15CuO₂: the prototype of cuprate family of oxide superconductors

Abstract

The layer-type compound, Ca_0·85Sr_0·15CuO₂, which is the prototype of the cuprate family of high T_c oxide superconductors is an electronic insulator, and has a low ordered moment at 300 K indicating that Cu²⁺ ions are highly correlated. Doping with lithium (up to x=0·15) decreases the room temperature resistivity drastically (from 10³ ohm·cm to 0·6 ohm·cm) but metallic behaviour is not induced below 300 K. The magnetic moment on Cu²⁺ remains low but our studies did not show any antiferromagnetic ordering below 300 K in any of the Li-doped phases.