Domain Wall Dynamics in a Ferroelastic Spin Crossover Complex with Giant Magnetoelectric Coupling

Area of Science:

• Materials Science
• Solid-State Chemistry
• Magnetism and Spintronics

Background:

• Spin crossover (SCO) materials offer tunable magnetic properties based on external stimuli.
• Understanding the interplay between structural, magnetic, and electric properties is crucial for advanced material design.
• Ferroelasticity and polar phases are key features for multiferroic applications.

Purpose of the Study:

• To investigate the coupling between structural and spin state order parameters in a Mn(III) complex.
• To detect and characterize ferroelastic domain walls under mechanical stress.
• To explore the material's potential for multifunctionality, including magnetoelectric coupling.

Main Methods:

• Single-crystal X-ray diffraction to determine crystal structures and phase transitions.
• Resonant ultrasound spectroscopy to probe ferroelasticity and mechanical properties.
• Measurements of magnetoelectric coupling and electric polarization.

Main Results:

• Three distinct symmetry-breaking phase transitions (Cc → Pc → P1 → P1(1/2)) were identified.
• Ferroelastic domain walls were observed in response to mechanical stress.
• Significant changes in electric polarization and remanent polarization under pulsed magnetic fields were detected.

Conclusions:

• The Mn(III) complex exhibits strong coupling between strain, polarization, structural, and spin state order parameters.
• This material demonstrates multifunctionality, showcasing ferroelasticity, polar phases, and spin crossover behavior.
• The findings highlight a rare example of coupled order parameters in a spin crossover material for potential applications.