Evolution of superconductivity and weak magnetism in inclination interfaces of Bi, Sb and Bi1-xSbx (0.07 ≤x ≤ 0.2) alloys

Abstract

Using Quantum Design SQUID magnetometer, we studied the magnetic and superconducting properties of high quality inclination bicrystal interfaces of Bi, Sb and 3D topological insulator Bi1-xSbx (0.06 ≤ x ≤ 0.2). One or two superconducting phases with Tc ≤ 21 K and magnetic hysteresis loops on a diamagnetic background typical for strong type II superconductors were identified in Bi and some Bi-Sb nano-width interfaces. However, the other interfaces of Bi1-xSbx (0.06 ≤ x ≤ 0.2) as well as of Sb with a higher carrier density exhibit a superconducting transition and a ferromagnetic hysteresis loop or a dual loop (superimposed ferromagnetic and superconducting loops) against a paramagnetic background and thereby indicate the occurrence of superconductivity and weak ferromagnetism.