On the first-order phase transitions in a bistable large-spin systems (Mn12Ac and others)

TL;DR

This paper critiques recent claims of first-order phase transitions in large-spin systems, introduces a kinetic numerical method for transition rate calculations, and identifies a new critical transition field value.

Contribution

It presents a novel kinetic numerical approach for transition rates and corrects the critical transition field in large-spin bistable systems.

Findings

The transition rate calculation method was developed.

A new critical transition field value of 0.891 was identified.

The physical mechanism for quantum to classical transition was discussed.

Abstract

We have shown that recent report concerning the first-order phase transitions in the large-spin systems is inaccurate. A kinetic numerical method for making calculations of the transition rate in a bistable system as a function of temperature has been evolved and a new critical value of the transition field (h=0.891) has been found. A physical mechanism caused transition from quantum to classical behavior has been discussed.