Resonant photon absorption in the low spin molecule V15

TL;DR

This study demonstrates the use of micro-SQUID techniques to observe resonant photon absorption in a low spin molecular system, enabling time-resolved quantum spin state measurements at very low temperatures.

Contribution

It introduces a novel application of micro-SQUID for time-resolved, GHz-range photon absorption studies in molecular nanomagnets, highlighting its advantages over traditional EPR methods.

Findings

Resonant photon absorption observed in V15 molecular complex.

Line-width dominated by intra-molecular hyperfine interactions.

Potential to observe Rabi oscillations in molecular nanomagnets.

Abstract

We report the first study of the micro-SQUID response of a molecular system to electromagnetic radiation. The advantages of our micro-SQUID technique in respect to pulsed electron paramagnetic resonance (EPR) techniques consist in the possibility to perform time-resolved experiments (below 1 ns) on submicrometer sizes samples (about 1000 spins) at low temperature (below 100 mK). Resonant photon absorption in the GHz range was observed via low temperature micro-SQUID magnetization measurements of the spin ground state S = 1/2 of the molecular complex V15. The line-width essentially results from intra-molecular hyperfine interaction. The results point out that observing Rabi oscillations in molecular nanomagnets requires well isolated low spin systems and high radiation power. Our first results open the way for time-resolved observations of quantum superposition of spin-up and spin-down states in SMMs.