Electrical and structural properties of MgB2 films prepared by sequential deposition of B and Mg on the NbN buffered Si(100) substrate

TL;DR

This paper presents a simple sequential deposition method for MgB2 films on NbN-buffered Si(100) substrates, resulting in homogeneous superconducting films with high critical current density and a transition temperature of 36 K.

Contribution

It introduces a novel, straightforward fabrication process for MgB2 films that yields high-quality, nanogranular superconducting layers without crystalline MgO contamination.

Findings

MgB2 films are homogeneous and nanogranular.

Maximum Tc observed is 36 K.

Critical current density reaches 3x10^7 A/cm^2 at 13.2 K.

Abstract

We introduce a simple method of an MgB2 film preparation using sequential electron-beam evaporation of B-Mg two-layer (followed by in-situ annealing) on the NbN buffered Si(100) substrate. The Transmission Electron Microscopy analyses confirm a growth of homogeneous nanogranular MgB2 films without the presence of crystalline MgO. A sensitive measurement of temperature dependence of microwave losses shows a presence of intergranular weak links close the superconducting transition only. The MgB2 films obtained, about 200 nm thick, exhibit a maximum zero resistance critical temperature of 36 K and critical current density of 3x10^7 A/cm^2 at 13.2 K