Competition of ferromagnetism and superconductivity in Sc 3 InB

We present results of electronic structure calculations for the intermetallic perovskite Sc 3 InB with the full‐potential KKR‐LDA method. Sc 3 InB is a very promising candidate for a new superconductor (related to 8 K MgCNi 3 ) and can be regarded as a boron‐inserted cubic Sc 3 In, which is a high‐pressure allotropic form of the hexagonal weak ferromagnet Sc 3 In. We predict that cubic Sc 3 In can also be magnetic, whereas Sc 3 InB having large DOS in the vicinity of E F exhibits non‐magnetic ground state. Estimation of the electron–phonon coupling for Sc 3 InB gives λ ≃ 1. Furthermore, the effect of vacancies in Sc 3 InB 1– x and antisite disorder in Sc 3 (In‐B) on critical parameters is also discussed using the KKR–CPA method. All theoretical results support the possibility of the superconductivity onset in Sc 3 InB. 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. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)