Tracking Temperature Dependent Relaxation Times of Individual Ferritin Nanomagnets with a Wide-band Quantum Spectrometer

TL;DR

This study uses a wide-band quantum spectrometer to monitor the temperature-dependent spin relaxation of individual ferritin nanomagnets, revealing insights into their magnetic dynamics from cryogenic to room temperature.

Contribution

It introduces a method to track single ferritin nanomagnet relaxation times across a broad temperature range using nitrogen-vacancy centers in diamond.

Findings

Temperature-dependent spectral features match thermally induced magnetization reversals.

Determined the anisotropy barrier of single ferritin molecules.

Demonstrated magnetic sensing from Hz to GHz frequencies.

Abstract

We demonstrate the tracking of the spin dynamics of ensemble and individual magnetic ferritin proteins from cryogenic up to room temperature using the nitrogen-vacancy color center in diamond as magnetic sensor. We employ different detection protocols to probe the influence of the ferritin nanomagnets on the longitudinal and transverse relaxation of the nitrogen-vacancy center, which enables magnetic sensing over a wide frequency range from Hz to GHz. The temperature dependence of the observed spectral features can be well understood by the thermally induced magnetization reversals of the ferritin and enables the determination of the anisotropy barrier of single ferritin molecules.