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

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. •We study the nano-width inclination bicrystal interfaces of Bi, Sb, and 3D topological insulator Bi-Sb.•The bicrystal interfaces of Bi present superconductivity, while those of Sb and Bi-Sb exhibit superconductivity and weak magnetism.•The superconductivity of bicrystal interfaces results from the reconstruction of the rhombohedral crystal structure A7 under deformations.•We have found that the interfaces of Sb and Bi-Sb bicrystals develop characteristics of 3D topological insulators.