Speaker
Description
The magnetic and dielectric/ferroelectric properties couple to each other in magnetolectric materials. The magnetic field can influence and manipulate the electric polarization and/or the electric field influences and manipulates the magnetization in a material. ME is attractive from an applications perspective in insulating materials because large power dissipation due to electric currents is eliminated. Other potential applications include magnetic sensors, data storage , electric control of magnetic qubits and more. Usually, ME coupling is studied in inorganic oxides where spin orientations form ordered patterns – (anti)ferromagnets. Here, our results demonstrate ME coupling in molecule-based complexes that demonstrate a bistable spin state resulting from a change in the d orbital occupancy. This phenomenon, Spin State Crossovers (SSCs), can produce substantial changes in the crystal structure, lattice parameters, dielectric, optical, and mechanical properties of the material and are often sharp and hysteretic. We demonstrate that in a Mn(III) based complex, an applied magnetic field induces a spin state switching accompanied by a change in electric polarization due to symmetry breaking phase transition. I will follow this with more examples of magnetoelectric coupling at lower fields.
Spin crossover complexes are a large class of materials where the magnetic-field-induced switching can modify the structure and here we show that this is a route to ME coupling. The interplay of spin, charge, and lattice needed to create such magnetoelectric coupling is an intriguing challenge and a source of new discoveries.
