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Near-Room-Temperature Magnetoelectric Coupling via Spin Crossover in an Iron(II) Complex
Magdalena Owczarek1, Minseong Lee2, Shuanglong Liu3
1Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Angewandte Chemie (International Ed. in English)
|October 28, 2022
Summary
Magnetoelectric spin crossover compounds, [Fe(1bpp)2](BF4)2, demonstrate coupling near room temperature. This breakthrough utilizes molecular spin states to control electrical properties with low magnetic fields, paving the way for practical applications.
Area of Science:
- Molecular Magnetism
- Spin Crossover Materials
- Magnetoelectric Effects
Background:
- Spin crossover (SCO) compounds exhibit switching between high-spin and low-spin states.
- Magnetoelectric coupling, the control of magnetic properties by electric fields or vice versa, is typically observed at cryogenic temperatures.
- Achieving magnetoelectric coupling near room temperature in molecular SCO compounds remains a significant challenge for practical applications.
Purpose of the Study:
- To achieve and characterize magnetoelectric coupling near room temperature in a molecule-based spin crossover compound.
- To investigate the role of molecular structure and spin state transitions in magnetoelectric phenomena.
- To explore the potential for low magnetic field control of electrical properties in SCO materials at ambient conditions.
Main Methods:
- Synthesis and characterization of the [Fe(1bpp)2](BF4)2 spin crossover compound.
- Variable temperature and magnetic field studies to probe spin state transitions.
- Measurement of electric polarization and dielectric constant changes in response to magnetic field stimuli.
Main Results:
- Magnetoelectric coupling was successfully demonstrated near room temperature in [Fe(1bpp)2](BF4)2.
- Jahn-Teller distortions associated with spin state changes induce significant alterations in molecular dipole moment.
- A low magnetic field of 3 T was sufficient to induce changes in magnetic and electrical properties in the bistability region.
- Observed changes in H-induced electric polarization were in the range of 0.3-0.4 mC/m^2.
Conclusions:
- This study expands the operational range of magnetoelectric spin crossovers towards ambient conditions.
- The high strength of magnetoelectric coupling is accessible near room temperature, offering significant potential for device applications.
- Molecular spin crossover materials present a promising platform for developing novel magnetoelectric devices operating under practical conditions.
Keywords:
Magnetic PropertiesMagnetoelectric CouplingMolecular MagnetSpin CrossoverStructural Phase TransitionMore Related Videos
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