Competition of ferromagnetism and superconductivity in Sc3InB

Abstract

We present results of electronic structure calculations for intermetallic perovskite Sc3InB with Full--Potential KKR-LDA method. Sc3InB is very promising candidate for a new superconductor (related to 8K MgCNi3) and can be regarded as a boron-inserted cubic Sc3In, which is a high--pressure allotropic form of the hexagonal weak ferromagnet Sc3In. We predict that cubic Sc3In can be also magnetic, whereas Sc3InB having large DOS in the vicinity of EF exhibits non-magnetic ground state. Estimation of the electron--phonon coupling for Sc3InB gives $\lambda \simeq 1$. Furthermore, the effect of vacancy in Sc3InB{1-x} and antisite disorder in Sc3(In-B) on critical parameters is also discussed in view of KKR--CPA method. All theoretical results support possibility of the superconductivity onset in Sc3InB. Preliminary experimental measurements established the transition temperature close to 4.5 K, with a very abrupt change in susceptibility and a correlated drop of the resistivity when cooling down.