Eur. Phys. J. B 30, 147-151 (2002)
https://doi.org/10.1140/epjb/e2002-00369-4

Angular dependence of magnetoresistivity in c-oriented MgB₂ thin film

¹ INFM-LAMIA, Dipartimento di Fisica, Via Dodecaneso 33, 16146 Genova, Italy
² IMEM/CNR, Dipartimento di Fisica, Via Dodecaneso 33, 16146 Genova, Italy
³ INFM, Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31,16146 Genova, Italy

Corresponding author: ^a Ferdeghini@fisica.unige.it

Received: 12 July 2002
Revised: 17 September 2002
Published online: 29 November 2002

Abstract

The anisotropy of MgB₂ is still under debate: its value, strongly dependent on the kind of sample and on the measuring method, ranges between 1.2 and 13. In this work we present our results on 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 θ 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. Some differences in the upper critical field and in its anisotropy of our film with respect to single crystals are emphasized: some of these aspects can be accounted for by an analysis of upper critical fields within a two-band model in presence of disorder and/or crystallographic strain.