Spectroscopic Analysis of Molecular Magnetic Materials

Abstract

The pervasive character of spin-phonon or vibronic coupling in the field of molecular magnetism highlights its significance. Importantly, this phenomenon mediates magnetic relaxation in single-molecule magnets (SMMs), leading to undesirable memory loss which limits their potential as nanoscale storage units. It is therefore essential to gain a complete picture and develop design strategies to enable controlled manipulation of the vibronic coupling, thus improving magnetic relaxation rates in SMMs. Gaining direct evidence of vibronic coupling via experimental means and validating with theoretical calculations is key to achieving this goal. In this thesis, we present three distinct studies, all unified by the application of ab initio calculations to analyse the vibronic coupling in a variety of dysprosium(III) SMMs. The first paper investigates the magnetic relaxation dynamics of a high-performance SMM by an integration of magnetometry measurements with spin dynamics calculations, which offer a comprehensive insight into the different relaxation mechanisms present. The second study explores the chiral control of magnetic relaxation dynamics by examining two pairs of enantiomers with superposed axial and point chirality. A synergy of experimental and theoretical analysis, including state-of-the-art solid-state ab initio computations, reveal structural and magnetic differences between diastereomers that are explored. The third work compares the vibronic coupling in two complexes of opposing magnetic anisotropy, using contemporary spectroscopic measurements to uncover the effect of anisotropy on the spin-phonon coupling.

Date of Award	31 Dec 2024
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Eric Mcinnes (Supervisor) & Nicholas Chilton (Supervisor)