Observation of conduction electron spin resonance in boron doped diamond

TL;DR

This study reports the first observation of conduction electron spin resonance in boron-doped superconducting diamond, revealing key spin properties and anomalies related to electron spin dynamics in this material.

Contribution

It provides the first experimental detection of CESR in boron-doped diamond and analyzes its spin relaxation properties and anomalies.

Findings

CESR signal intensity is temperature independent and matches Pauli susceptibility.

CESR linewidth weakly increases with temperature, consistent with Elliott-Yafet theory.

An unexplained relation between g-factor, linewidth, and resistivity was observed.

Abstract

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.