Narrow Zero-Field Tunneling Resonance in Triclinic Mn$_{12}$ Acetate Ribbons

TL;DR

This study synthesizes amorphous Mn12-acetate ribbons with a unique triclinic short-range order, revealing narrower zero-field tunneling resonances than traditional crystals, which suggests reduced inhomogeneous broadening.

Contribution

It introduces a new amorphous form of Mn12-acetate with a triclinic structure and demonstrates its magnetic resonance properties are similar but with significantly narrower zero-field resonances.

Findings

Zero-field resonance width is at least ten times smaller in ribbons.

Ribbons exhibit the same tunneling resonance positions as crystalline Mn12-acetate.

The reduced broadening indicates less inhomogeneous magnetic fields.

Abstract

We report synthesis, structural characterization, and magnetic measurements of amorphous Mn$_{12}$-acetate ribbons with a triclinic short-range crystal order not previously seen in experiment. The ribbons exhibit the same structure of Mn$_{12}$ molecules and the same positions of tunneling resonances on the magnetic field as a conventional tetragonal Mn$_{12}$-acetate crystal. However, the width of the zero-field resonance is by at least one order of magnitude smaller, indicating very small inhomoge- neous broadening due to dipolar and nuclear fields. Possible origins of this effect are discussed.