Resonant Tunneling in Truly Axial Symmetry Mn12 Single-Molecule Magnets: Sharp Crossover between Thermally Assisted and Pure Quantum Tunneling

TL;DR

This study investigates resonance tunneling in a highly symmetric Mn12 nanomagnet, revealing detailed crossover behavior between thermally assisted and pure quantum tunneling through precise hysteresis measurements.

Contribution

It provides detailed experimental evidence and modeling of the crossover between thermally assisted and pure quantum tunneling in a highly symmetric Mn12 nanomagnet.

Findings

Resonance tunneling observed in Mn12-tBuAc nanomagnet.

Well-resolved step fine-structure due to level crossings.

Crossover between thermally assisted and pure quantum tunneling characterized.

Abstract

Magnetization measurements of a truly axial symmetry Mn12-tBuAc molecular nanomagnet with a spin ground state of S = 10 show resonance tunneling. This compound has the same magnetic anisotropy as Mn12-Ac but the molecules are better isolated and the crystals have less disorder and a higher symmetry. Hysteresis loop measurements at several temperatures reveal a well-resolved step fine-structure which is due to level crossings of excited states. All step positions can be modeled by a simple spin Hamiltonian. The crossover between thermally assisted and pure quantum tunneling can be investigated with unprecedented detail.