Superconducting phase diagram of lanthanum films on the substrate of Si(100)

Lanthanum films were grown on the substrate of Si(100) (La/Si(100)) by the molecular beam epitaxy (MBE) method and their superconducting properties were studied via the magnetic and electrical transport measurements. The superconducting transition temperature (Tc) is around 5.3 K. Besides, the second magnetization peak (SMP) occurs well below the upper critical field Hc2(T) due to the thermomagnetic flux-jump instabilities. In addition, we also calculated the critical current density (Jc) and studied the vortex-pinning behavior. The Jc is higher than 10 MA/cm2 at certain temperatures. The pinning analysis suggests the dominant role is the δl pinning. Moreover, the comprehensive superconducting phase diagram is offered. Our study completes the superconducting properties of lanthanum, which would facilitate the understanding of superconducting mechanism in the type Ⅱ superconductors.