Rare earth substitution in lattice-tuned Sr0.3Ca0.7Fe2As2 solid solutions

Abstract

The effects of aliovalent rare earth substitution on the physical properties of Sr0.3Ca0.7Fe2As2 solid solutions are explored. Electrical transport, magnetic susceptibility and structural characterization data as a function of La substitution into (Sr_1-y_Ca_y)_1-x_La_x_Fe2As2 single crystals confirm the ability to suppress the antiferromagnetic ordering temperature from 200 K in the undoped compound down to 100 K approaching the solubility limit of La. Despite up to ~30% La substitution, the persistence of magnetic order and lack of any signature of superconductivity above 10 K present a contrasting phase diagram to that of Ca1-xLaxFe2As2, indicating that the suppression of magnetic order is necessary to induce the high-temperature superconducting phase observed in Ca1-xLaxFe2As2.Comment: Submitted to Superconductor Science and Technology focus issue: "Fe-based superconductors: materials, theory, experiment and applications (Iron 12)