Volume 81, Number 6, March 2008
Article Number 67006
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 29 February 2008
EPL, 81 (2008) 67006
DOI: 10.1209/0295-5075/81/67006

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

M. Monni1, 2, I. Pallecchi2, C. Ferdeghini2, V. Ferrando2, A. Floris3, E. Galleani d'Agliano2, E. Lehmann4, I. Sheikin5, C. Tarantini2, X. X. Xi6, S. Massidda1 and M. Putti2

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 in final form 30 January 2008; published March 2008
published online 29 February 2008

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 (0$\hbox{--} $28 T) and temperatures (40$\hbox{--} $300 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 $\sigma $-carriers.

72.10.Di - Scattering by phonons, magnons, and other nonlocalized excitations.
73.43.Qt - Magnetoresistance.
74.70.Ad - Metals; alloys and binary compounds (including A15, MgB2, etc.).

© EPLA 2008