Pulsed rotational drift spectroscopy sequences for magnetorelaxometry

Abstract

Rotational Drift Spectroscopy (RDS) is a novel spectroscopic method for magnetic nanoparticles. It is based on measuring therotational drift of magnetic nanoparticle ensembles in a rotating magnetic field, which is below the magnetic field strength necessary forrotating the magnetic nanoparticles synchronously. Magnetorelaxometry (MRX) measures the decaying magnetization after applying amagnetic pulse, allowing to determine the zero-field relaxation time of magnetic particle systems. It is used, e.g., for general particlecharacterization or bioassay applications. The following work presents pulsed RDS sequences for measuring the zero-field relaxationbehavior of magnetic particles. Measuring the zero-field relaxation using an RDS setup provides the advantage of allowing the combinationof additional measurement sequences for more specific particle characterizations. The pulse sequence can be tailored to the necessaryrelaxation time range of the particle system, allowing to cover a wide range of different relaxation times.