Inclusions of metastable superconducting phase of gallium in SmGa$_2$

The magnetization M of the SmGa$_2$ compound has a paramagnetic character in a wide temperature range, and when the temperature decreases below 30 K, a significant increase in magnetization is observed, which indicates the formation of a magnetically ordered state. At temperatures below 5 K, a sharp feature is observed on the M(H) dependences, which is the contribution from the magnetization of superconducting submicron gallium inclusions. Analysis of the M(H) dependences measured at different temperatures below 5 K allowed us to assume the presence of two superconducting gallium phases. The critical temperature T$_C$ = 5.9 K and the critical field H$_C$ (0) = 560 Oe correspond to the formation of a metastable $\beta$-phase of gallium, and the critical temperature T$_C$ = 8.4 K and the critical field H$_C$ (0) = 1100 Oe can be associated with the formation of a thin layer of amorphous gallium on the surface of the $\beta$-phase inclusions.