Probing the electron-phonon coupling in MgB₂ through magnetoresistance measurements in neutron irradiated thin films

¹  CNR-INFM-SLACS and Dipartimento di Fisica, Università di Cagliari - Cittadella Universitaria, I-09124 Monserrato (CA), Italy
²  CNR-INFM-LAMIA and Dipartimento di Fisica, Università di Genova - Via Dodecaneso 33, I-16146 Genova, Italy
³  Institut für Theoretische Physik, Freie Universität Berlin - Arnimallee 14, D-14195 Berlin, Germany
⁴  Paul Scherrer Institut - CH-5232 Villigen, Switzerland
⁵  GHMFL, MPI-FKF/CNRS - 28 Avenue des Martyrs, BP 166, F-38042 Grenoble Cedex 9, France
⁶  The Pennsylvania State University - University Park, PA 16802, USA

Received: 11 December 2007
Accepted: 30 January 2008

Abstract

We report magnetoresistance (MR) measurements on MgB₂ and the corresponding full account from ab initio calculations; we suggest that this combination can be a useful tool to probe electron-phonon coupling. We obtain good quantitative agreement between high-field measurements on neutron-irradiated epitaxial thin films and calculations within Bloch-Boltzmann transport theory over a wide range of magnetic fields (028 T) and temperatures (40300 K), and as a function of the field orientation. The crossovers between in-plane and out-of-plane MR, experimentally observed as a function of either disorder or temperature are well reproduced indicating that disorder and interaction with phonons strongly affect the scattering rate of -carriers.