Dynamical Aspects of Photoinduced Magnetism and Spin-Crossover phenomena in Prussian Blue Analogs

TL;DR

This paper develops a unified dynamical model for photoinduced magnetism and spin-crossover phenomena in Prussian blue analogs, capturing complex temperature and photoirradiation effects on magnetic states.

Contribution

It introduces a new model integrating spin-crossover and magnetic ordering, successfully reproducing observed behaviors in Prussian blue analogs.

Findings

Magnetization follows quasi-static processes at low temperatures.

Coupled dynamics of spin states and magnetization show cooperative phenomena.

Temperature and photoirradiation control lead to diverse dynamical behaviors.

Abstract

We present dynamical properties of spin crossover compounds with photomagnetization, proposing a new model in which the spin-crossover phenomena and magnetic ordering are incorporated in a unified way. By using this model, the novel characteristics observed in Prussian blue analogs are qualitatively well reproduced. We investigate the time evolution of the magnetization and high spin fraction taking into account multi-time scales in a master equation approach for the magnetic relaxation, the lattice (electronic) relaxation, and the photoexcitation process. In particular, processes with different temperature cycles starting from the photoinduced saturated magnetic state are studied including the effect of photoirradiation. In the temperature cycle in the low temperature region where the high spin state has a strong metastability, the magnetization almost exactly follows the quasi-static process. On the other hand, when the temperature is raised above the region, the dynamics of the spin state and the magnetization couple and exhibit various types of dynamical cooperative phenomena under time-dependent control of temperature and photoirradiation.