Decay of Rabi oscillations induced by magnetic dipole interactions in diluted paramagnetic solids

TL;DR

This paper analyzes how magnetic dipole interactions cause decay in Rabi oscillations of diluted paramagnetic spins in solids, providing analytical models and experimental comparisons.

Contribution

It introduces analytical expressions for Rabi oscillation decay considering dipole interactions and spin distribution effects in paramagnetic solids.

Findings

Decay rate depends on microwave field intensity and spin concentration.

Analytical models match experimental data for silica and quartz.

Dipole interactions cause frequency shifts leading to signal decay.

Abstract

Decay of Rabi oscillations of equivalent spins diluted in diamagnetic solid matrix and coupled by magnetic dipole interactions is studied. It is shown that these interactions result in random shifts of spin transient nutation frequencies and thus lead to the decay of the transient signal. Averaging over random spatial distribution of spins within the solid and over their spectral positions within magnetic resonance line, we obtain analytical expressions for the decay of Rabi oscillations. The rate of the decay in the case when the half-width of magnetic resonance line exceeds Rabi frequency is found to depend on the intensity of resonant microwave field and on the spin concentration. The results are compared with the literature data for E1' centers in glassy silica and [AlO4] centers in quartz.