ODMR-Based Resonant Spin Inertia: A Sensitive Technique for Studying Spin Relaxation

We describe the principle and applications of the resonant spin inertia technique that is based on optically detected magnetic resonance. It combines optical pumping and Faraday/Kerr rotation probing in a single laser beam and measures spin resonance and the spin inertia effect induced by a modulated radiofrequency field. This method is sensitive, technically simple, and applicable to a wide range of material systems. It provides access to the basic spin properties, including the longitudinal spin relaxation time T₁ T 1 , which can be measured selectively for different spin resonances present in the system. We demonstrate the application of the technique to rare-earth Ce ³⁺ 3 + ions in a YAG matrix, (In,Ga)As/GaAs quantum dots, and lead halide perovskite nanocrystals. The technique allowed to measure T₁ T 1 in these systems, ranging from microseconds to milliseconds, and to reveal peculiarities of spin relaxation for charge carriers as well as for spatially indirect excitons.