  Lithium Niobate (LN) is a ferroelectric material with exceptional electrical
characteristics, including high piezoelectricity, high Pockels effect, etc.
These properties make it a promising platform for numerous fields such as
high-speed communication, optical computation, and quantum information
processing. Besides these, the introduction of magnetic structures to LN holds
significant potential to achieve magnetoelectric coupling, which can be applied
in magnetic memory and data-processing devices with high efficiency. Here, for
the first time, we observe a special topological magnetic structure called
magnetic skyrmion in LN (SK-LN) by the combination of magnetic field annealing
and rapid annealing processes . Compared to the magnetic skyrmions reported in
magnetic systems, SK-LN exhibit exceptionally high stability. Additionally, the
center of the magnetic vortex exhibits spontaneous ferroelectric polarization,
indicating its multiferroic characteristic. With the excitation of these
multiferroic skyrmions, the modulation efficiency of the electro-optical (EO)
modulator fabricated on thin film lithium niobate on insulator (LNOI) wafer was
found to be enhanced from 1.98 V*cm to 0.63 V*cm. It is considered that the
multiferroic skyrmions significantly enhance the Pockels coefficient of LN to
101 pm/V, nearly three times the result (32pm/V) reported previously.
