Laser-Induced Magnetization Precession in Individual Magnetoelastic Domains of a Multiferroic Co 40 Fe 40 B 20 / Ba Ti O 3 Composite

Using a magneto-optical pump-probe technique with micrometer spatial resolution, we show that magnetization precession can be launched in individual magnetic domains imprinted in a ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}$ layer by elastic coupling to ferroelectric domains in a ${\mathrm{Ba}\mathrm{Ti}\mathrm{O}}_{3}$ substrate. The dependence of the precession parameters on the strength and orientation of the external magnetic field reveals that laser-induced ultrafast partial quenching of the magnetoelastic coupling parameter of ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}$ by approximately 27% along with 10% ultrafast demagnetization triggers the magnetization precession. The relation between the laser-induced reduction of the magnetoelastic coupling and the demagnetization is approximated by an $n(n+1)/2$ law with $n\ensuremath{\approx}2$. This correspondence confirms the thermal origin of the laser-induced anisotropy change. Based on analysis and modeling of the excited precession, we find signatures of laser-induced precessional switching, which occurs when the magnetic field is applied along the hard magnetization axis and its value is close to the effective magnetoelastic anisotropy field. The precession-excitation process in an individual magnetoelastic domain is found to be unaffected by neighboring domains. This makes laser-induced changes of magnetoelastic anisotropy a promising tool for driving magnetization dynamics and switching in composite multiferroics with spatial selectivity.