title: Using ultrashort optical pulses to couple ferroelectric and ferromagnetic order in an oxide heterostructure.
abstract: A new approach to all-optical detection and control of the coupling between electric and magnetic order on ultrafast timescales is achieved using time-resolved second-harmonic generation (SHG) to study a ferroelectric (FE)/ferromagnet (FM) oxide heterostructure. We use femtosecond optical pulses to modify the spin alignment in a Ba(0.1)Sr(0.9)TiO3 (BSTO)/La(0.7)Ca(0.3)MnO3 (LCMO) heterostructure and selectively probe the ferroelectric response using SHG. In this heterostructure, the pump pulses photoexcite non-equilibrium quasiparticles in LCMO, which rapidly interact with phonons before undergoing spin-lattice relaxation on a timescale of tens of picoseconds. This reduces the spin-spin correlations in LCMO, applying stress on BSTO through magnetostriction. This then modifies the FE polarization through the piezoelectric effect, on a timescale much faster than laser-induced heat diffusion from LCMO to BSTO. We have thus demonstrated an ultrafast indirect magnetoelectric effect in a FE/FM heterostructure mediated through elastic coupling, with a timescale primarily governed by spin-lattice relaxation in the FM layer.
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, MS K771, Los Alamos, New Mexico 87545, USA.
authors.forename: Y M
authors.initials: YM
authors.lastname: Sheu
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, MS K771, Los Alamos, New Mexico 87545, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Trugman
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, MS K771, Los Alamos, New Mexico 87545, USA.
authors.forename: L
authors.initials: L
authors.lastname: Yan
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, MS K771, Los Alamos, New Mexico 87545, USA.
authors.forename: Q X
authors.initials: QX
authors.lastname: Jia
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, MS K771, Los Alamos, New Mexico 87545, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Taylor
authors.affiliation: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, MS K771, Los Alamos, New Mexico 87545, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Prasankumar