Landau-Zener tunneling with many-body quantum effects in crystals of molecular magnets

TL;DR

This paper provides a quantum interpretation of hysteresis in Fe8 molecular magnets, modeling the crystal as an interacting Ising spin system and explaining experimental observations of quantum tunneling effects.

Contribution

It introduces a quantum model for hysteresis in molecular magnets considering dipolar interactions, aligning theory with experimental data in different dynamical regimes.

Findings

Quantum interpretation matches experimental hysteresis data

Hysteresis steps are explained as quantum tunneling phenomena

Model applies to both rapid and adiabatic regimes

Abstract

We present a quantum interpretation of the heights in hysteresis of $Fe_{8}$ molecule at lower temperatures by treating the crystal as an Ising spin system with the dipolar interaction between spins. Then we apply it to two limit cases : rapid and adiabatic regions. Our theoretical analysis is in agreement with the experimental observation in these regions, which indicates that the steps in hysteresis loops of magnetization of Fe$_{8}$ at lower temperatures show a pure quantum process.