Giant magnetoelectric coupling and low magnetic field switching demonstrated in spin crossover complex

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Inorganic Chemistry featured the work on its cover. Here, a Mn3+ complex in shown magnetoelectric coupling at a spin crossover. The spin crossover between the high-spin (HS) and low-spin (LS) states (shown as a switch) triggers a structural phase transition between different polar space groups. The graphic shows an artist's rendition of the electric and magnetic field lines in the sample.

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In work recently published in Inorganic Chemistry, LANL researchers in the National High Magnetic Field Laboratory-Pulsed Field Facility (MPA-MAGLAB) and their international collaborators investigated the combination of relatively low magnetic field switching and giant magnetoelectric (ME) coupling in a molecule-based spin crossover (SCO) complex. The combination showcases the potential for applications in spin crossover materials.

Magnetoelectric coupling occurs when a material’s magnetic field influences the electric polarization and dielectric constant, the amount of electric energy storage of a material. Such coupling may also occur when the electric field influences the magnetization. The intriguing materials phenomenon has applications that range from electric control of spacers between magnetic qubits sensors to data storage, tunable antennas, and other frequency devices. However, not all of the materials needed to realize these diverse applications have been discovered.

LANL researchers and their collaborators departed from traditional studies using inorganic oxides with ordered magnetic spin orientations. Their investigation of the phenomena of field switching and giant ME coupling in an SCO complex indicates the potential of SCO materials for future applications involving magnetoelectric coupling. Those applications may include switching, magnetic and electric sensing, and controlling quantum computers.

The research team conducted research on single crystals and reported ME coupling—near the SCO critical temperature—between spin state, structure, and electric polarization in the Jahn Teller complex due to a first order phase transition. Notably, the SCO behavior is driven by a field as low as 8.7 T, which is remarkably low compared to most other magnetic-field-induced SCO materials. The study demonstrates a giant magnetoelectric effect with a field-induced electric polarization change that is one-tenth of the record for any material.

Funding and Mission

The work supports the Lab’s Energy Security mission and its Materials for the Future science pillar. The LANL science portion of the research was driven and funded by M2QM, the Center for Molecular Magnetic Quantum Materials, an Energy Frontier Research Center funded by the DOE, Office of Science, Basic Energy Sciences. The NHMFL-Pulsed Field Facility provided uniquely high magnetic fields and fast pulsed fields that improve measurement sensitivity to ME coupling. The NHMFL is funded by the National Science Foundation, the state of Florida, and the U.S. DOE. The work supports the Lab’s Energy Security Mission and Materials for the Future capability pillar.

Reference

“Giant Magnetoelectric Coupling and Magnetic-Field-Induced Permanent Switching in a Spin Crossover Mn(III) Complex,” Inorganic Chemistry, 60, 9, 6167 (2020). DOI: https://doi.org/10.1021/acs.inorgchem.0c02789. Authors: Vivien S. Zapf, Shalinee Chikara, Xiaxin Ding, Franziska Weickert (National High Magnetic Field Laboratory-Pulsed Field Facility, MPA-MAGLAB); Grace G. Morgan, Vibe B. Jakobsen, Emiel Dobbelaar, Conor T. Kelly (University College Dublin); Jie-Xiang Yu, Hai-Ping Cheng (University of Florida); Elzbieta Trzop, and Eric Collet (CNRS, Institut de Physique de Rennes).

Technical contact: Vivien Zapf