Superconductivity and ferromagnetism in twisting Bi-Sb interfaces

Abstract

The hysteresis loops and temperature dependences of magnetic moment m(T) are studded in large disorientation angle (LDA) twisting interfaces of Bi1-xSbx (0 < x < 0. 2) alloys. They were found one superconducting transition with Tc ~ 3.7 - 4.6K (for various samples) and magnetic hysteresis loops typical for weak ferromagnetic materials. The values of upper critical Hc2 (T) and dHc2/dT in LDA interfaces were somewhat lower than in small disorientation angle interfaces with two superconducting transition. For instance, Hc2(T) and dHc2/dT, depending on the sample composition, take values of ≈ 2.6–3.7kOe and - (0.9–1.5)kOe/K, respectively. They corresponds to the zero-temperature coherence length ξ ≈ 30 - 35nm and superconducting layer thickness about 100-120nm.