The spin-lattice relaxation time, T1, of conduction electrons is measured as a function of temperature and magnetic field in MgB2. The method is based on the detection of the z component of the conduction electron magnetization under electron spin resonance conditions with amplitude modulated microwave excitation. Measurement of T1 below Tc at 0.32 T allows to disentangle contributions from the two Fermi surfaces of MgB2 as this field restores normal state on the Fermi surface part with π symmetry only.
@article{arxiv.0704.0466,
title = {Conduction electron spin-lattice relaxation time in the MgB2 superconductor},
author = {F. Simon and F. Murányi and T. Fehér and A. Jánossy and L. Forró and C. Petrovic and S. L. Bud'ko and P. C. Canfield},
journal= {arXiv preprint arXiv:0704.0466},
year = {2009}
}