Consequence of isovalent rare earth substitution to magnetic irreversibility in cation-stoichiometric CuBa2RECu2O6.93±0.01

Abstract

For a series of CuBa2RECu2O7−δ (Cu−1(Ba)2RE12; RE= rare earth element) single-phase cation-stoichiometric samples with a fixed oxygen content, δ=0.07±0.01, a clear dependence of the Hirr characteristics on the ionic radius of RE is revealed. With decreasing ionic radius of RE, the Hirr characteristics are remarkably enhanced such that the samples containing heavy REs exhibit very high Hirr values. This result implies that through isovalent cation substitution alone carrier-density distribution and thereby the superconductivity characteristics may be controlled.