Events on Thursday, November 21st, 2024
- Pressure and Strain Control of Multiferroic Order in NiI2
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Shua Sanchez, MIT
- Abstract: Multiferroic materials exhibit a linear coupling between simultaneous magnetic and
ferroelectric orders, a rare and unexpected phenomenon. These intriguing materials have attracted
great interest as a platform for energy-efficient computing by using electric fields to control magnetic
states. The van der Waals material NiI2 has been identified as the first multiferroic material in the 2D
limit. Here, a magnetic spin spiral forms between Ni atoms, which breaks inversion symmetry and
induces a ferroelectric polarization. These electronic orders also break the rotational symmetry of the
lattice, enabling structural tuning parameters to directly couple to them. In this talk, I will discuss
pressure and strain tuning measurements of NiI2 which demonstrate the high degree of tunability of
this system, as characterized by x-ray, Raman, and polarimetry measurements. We observe that
transition temperatures can be strongly enhanced by pressure. Further, strain-tuning is shown to control
the polarization direction of the electronic orders. These results present a path forward for structural
custom tuning of multiferroics to realize the goal of ultrafast state switching. - Host: Victor Brar