We observe the electron spin resonance of conduction electrons in boron doped (6400 ppm) superconducting diamond (Tc =3.8 K). We clearly identify the benchmarks of conduction electron spin resonance (CESR): the nearly temperature independent ESR signal intensity and its magnitude which is in good agreement with that expected from the density of states through the Pauli spin-susceptibility. The temperature dependent CESR linewidth weakly increases with increasing temperature which can be understood in the framework of the Elliott-Yafet theory of spin-relaxation. An anomalous and yet unexplained relation is observed between the g-factor, CESR linewidth, and the resistivity using the empirical Elliott-Yafet relation.
@article{arxiv.1305.2366,
title = {Observation of conduction electron spin resonance in boron doped diamond},
author = {Péter Szirmai and Gábor Fábián and János Koltai and Bálint Náfrádi and László Forró and Thomas Pichler and Oliver A. Williams and Soumen Mandal and Christopher Bäuerle and Ferenc Simon},
journal= {arXiv preprint arXiv:1305.2366},
year = {2013}
}