# Ultrafast Terahertz Field Control of the Emergent Magnetic and Electronic Interactions at Oxide Interfaces

## TL;DR

Researchers used ultrafast THz pulses to control magnetic and electronic states at oxide interfaces, offering a new way to design energy-efficient devices.

## Contribution

The study demonstrates ultrafast THz field control of ferromagnetic and electronic interactions in oxide superlattices.

## Key findings

- Sub-picosecond demagnetization of the ferromagnetic interfacial layer was observed.
- Slower dynamics indicate a change in the magnetic state due to spin-lattice coupling.
- THz pulses enable efficient control of 2D ferromagnetic states at oxide interfaces.

## Abstract

Ultrafast electric‐field control of emergent electronic and magnetic states at oxide interfaces offers exciting prospects for the development of the next generation of energy‐efficient devices. Here, it is demonstrated that the electronic structure and emergent ferromagnetic interfacial state in epitaxial LaNiO3/CaMnO3 superlattices can be effectively controlled using intense, single‐cycle THz electric‐field pulses. A suite of advanced X‐ray spectroscopic techniques is employed to measure a detailed magneto‐optical profile and the thickness of the ferromagnetic interfacial layer. Then, a combination of time‐resolved and temperature‐dependent optical measurements is used to disentangle several correlated electronic and magnetic processes driven by ultrafast, high‐field THz pulses. Sub‐picosecond non‐equilibrium Joule heating of the electronic system is observed, ultrafast demagnetization of the ferromagnetic interfacial layer, and slower dynamics indicative of a change in the magnetic state of the superlattice due to the transfer of spin‐angular momentum to the lattice. These findings suggest a promising avenue for the efficient control of 2D ferromagnetic states at oxide interfaces using ultrafast electric‐field pulses.

Intense single‐cycle THz electric‐field pulses enable ultrafast control of emergent electronic and magnetic states at LaNiO3/CaMnO3 interfaces. Combined X‐ray and optical probes reveal sub‐picosecond demagnetization driven by spin‐polarized currents and slower magnetoelastic dynamics linked to spin–lattice coupling. These intertwined processes uncover a pathway to manipulate interfacial ferromagnetism in correlated oxides using ultrafast THz‐field control.