Enhancing the barrier height for Yb(iii) single-ion magnets by modulating axial ligand fields

Abstract

The effect of systematic modification of the axial ligand field X on U_eff values in Yb(III)-based SIMs, [Yb(Ph₃PO)₄X₂]X′ (X, X′ = NO₃ (1), OTf (2) and X = I/Br/Cl; X′ = I₃ (3)), whose equatorial Ph₃PO ligation remains unchanged, has been investigated. Combined magnetic studies coupled with ab initio calculations reveal weakening of the axial ligand fields leading to the increase in the energy barrier, apart from suggesting the operation of different relaxation pathways.