Quantum nucleation in a single-chain magnet

TL;DR

This paper investigates the magnetization reversal in a single-chain magnet, revealing a transition from thermal to quantum nucleation mechanisms at low temperatures, with implications for understanding quantum effects in magnetic systems.

Contribution

It introduces a model combining thermal and quantum nucleation processes to explain magnetization reversal in single-chain magnets at low temperatures.

Findings

H_n increases with decreasing T and increasing v at higher temperatures.

Below 1 K, H_n becomes temperature independent, indicating quantum nucleation.

Magnetization reversal at very low T is driven by quantum nucleation of domain walls.

Abstract

The field sweep rate (v=dH/dt) and temperature (T) dependence of the magnetization reversal of a single-chain magnet (SCM) is studied at low temperatures. As expected for a thermally activated process, the nucleation field (H_n) increases with decreasing T and increasing v. The set of H_n(T,v) data is analyzed with a model of thermally activated nucleation of magnetization reversal. Below 1 K, H_n becomes temperature independent but remains strongly sweep rate dependent. In this temperature range, the reversal of the magnetization is induced by a quantum nucleation of a domain wall that then propagates due to the applied field.