Structural, magnetic, and transport properties of La2Cu1-xLixO4.

Abstract

Li substitutes for Cu in La{sub 2}CuO{sub 4} up to the limiting stoichiometry La{sub 2}Cu{sub 0.5}Li{sub 0.5}O{sub 4}, which has superstructure order. The effects of this in-plane hole doping on the structural and magnetic properties of La{sub 2}CuO{sub 4} are very similar to those due to Sr substitution. The tetragonal-orthorhombic structural phase transition occurs, for a given amount of Sr or Li, at nearly the same temperature, and the in-plane lattice constant of La{sub 2{minus}{ital y}}Sr{sub {ital y}}Cu{sub 1{minus}{ital x}}Li{sub {ital x}}O{sub 4} at room temperature depends only on the combined hole count ({ital x}+{ital y}) and not on the individual Sr or Li concentration. Long-range magnetic order is destroyed upon substituting 3{percent} Li for Cu, analogous to the effect of Sr substitution on {ital T}{sub N{acute e}el}. However, the holes introduced by Li substitution are bound. The resistivity as a function of temperature is nonmetallic for all Li concentrations. {copyright} {ital 1996 The American Physical Society.}