H-T phase diagram and the nature of Vortex-glass phase in a quasi two-dimensional superconductor: Sn metal layer sandwiched between graphene sheets

The magnetic properties of a quasi two-dimensional superconductor, Sn-metal graphite (MG), are studied using DC and AC magnetic susceptibility. Sn-MG has a unique layered structure where Sn metal layer is sandwiched between adjacent graphene sheets. This compound undergoes a superconducting transition at $T_{c}$ = 3.75 K at $H$ = 0. The $H$-$T$ diagram of Sn-MG is similar to that of a quasi two-dimensional superconductors. The phase boundaries of vortex liquid, vortex glass, and vortex lattice phase merge into a multicritical point located at $T^{*}$ = 3.4 K and $H^{*}$ = 40 Oe. There are two irreversibility lines denoted by $H_{gl}$ (de Almeida-Thouless type) and $H_{gl^{\prime}}$ (Gabay-Toulouse type), intersecting at $T_{0}^{\prime}$= 2.5 K and $H_{0}^{\prime}$ = 160 Oe. The nature of slow dynamic and nonlinearity of the vortex glass phase is studied.