Ultrafast terahertz field control of the emergent electronic and magnetic interactions at the CaMnO₃/LaNiO₃ ferromagnetic interface

Ultrafast electric-field control of electronic and magnetic dynamics in oxide materials has great potential as a strategy for the future development of faster and more efficient logic and memory devices. LaNiO₃/CaMnO₃ superlattices display emergent ferromagnetism at the interface of paramagnetic LaNiO₃ and antiferromagnetic CaMnO₃ which can be tuned via control of the thickness-dependent metal-insulator transition in LaNiO₃. We utilized temperature- and fluence-dependent time-resolved magneto-optic Kerr effect, optical reflectivity, and transmissivity spectroscopies of variable-thickness LaNiO₃/CaMnO₃ superlattices to disentangle multiple interrelated electronic and magnetic processes driven by ultrafast high-field terahertz pulses. Detailed analysis of temperature- and field-dependent amplitudes and time constants for the various electronic and magnetic components of the dynamics are presented. These findings suggest an avenue for efficient electric-field switching of two-dimensional ferromagnetic states at oxide interfaces.

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