Quantum dynamics of Mn$^{2+}$ in dimethylammonium magnesium formate

TL;DR

This study investigates the quantum dynamics of Mn$^{2+}$ ions in a hybrid perovskite-like dielectric material using multifrequency electron spin resonance, revealing phase-dependent magnetic structures and local disorder effects.

Contribution

It provides new insights into the quantum behavior of Mn$^{2+}$ ions in DMAMgF across phase transitions using advanced EPR techniques and DFT computations.

Findings

High local disorder in the paraelectric phase evidenced by zero field splitting

Detection of two magnetic structures in the ferroelectric phase

Application of Rabi oscillation and kernel density estimation to analyze complex EPR signals

Abstract

Dimethylammonium magnesium formate, [(CH$_3$)$_2$NH$_2$][Mg(HCOO)$_3$] or DMAMgF, is a model to study high temperature hybrid perovskite-like dielectrics. This compound displays a phase transition from para to ferroelectric at about 260~K. Using multifrequency electron spin resonance in continuous wave and pulsed modes, we herein present the quantum dynamic of Mn$^{2+}$ ion probe in DMAMgF. In the high temperature paraelectric phase, we observe a large distribution of the zero field splitting that is attributed to high local disorder and further supported by DFT computations. In the low temperature ferroelectric phase, a single structure phase is detected and shown to contain two magnetic structures. The complex EPR signals were identifed by the means of Rabi oscillation method combined to crystal fields kernel density estimation.