Angular dependence of magnetoresistivity in c-oriented MgB2 thin film

TL;DR

This study investigates the anisotropy of MgB2 thin films through magnetoresistivity measurements, revealing temperature-dependent anisotropic behavior and comparing results with single crystals, contributing to understanding MgB2's anisotropic properties.

Contribution

The paper presents a detailed analysis of MgB2 thin film anisotropy using two measurement approaches, highlighting differences from single crystal data and discussing implications for its two-band superconductivity.

Findings

Anisotropy varies with temperature and measurement method.

Magnetoresistivity shows similar trends in different measurement approaches.

Comparison indicates differences between thin film and single crystal properties.

Abstract

The anisotropy of MgB2 is still under debate: its value, strongly dependent on the sample and on the measuring method, ranges between 1.2 and 13. In this work we present our results on a MgB2 c-oriented superconducting thin film. To evaluate the anisotropy, we followed two different approaches. Firstly, magnetoresistivity was measured as a function of temperature at selected magnetic fields applied both parallel and perpendicular to the c-axis; secondly, we measured magnetoresistivity at selected temperatures and magnetic fields, varying the angle q between the magnetic field and the c-axis. The anisotropy estimated from the ratio between the upper critical fields parallel and perpendicular to the c-axis and the one obtained in the framework of the scaling approach within the anisotropic Ginzburg-Landau theory are different but show a similar trend in the temperature dependence. The obtained results are compared and discussed in the light of the two-band nature of MgB2. A comparison between critical fields in thin films and single crystal is also performed.