  We fabricated Pt/La0.5Ba0.5MnO3 ultrathin films with integration to the
PbZr0.2Ti0.8O3 ferroelectric. Strong Topological Hall Effect can be measured
across a wide temperature range, which can be turned on and off corresponding
to the ferroelectric polarization switching driven by short voltage pulses,
indicating creation and annihilation of magnetic Skyrmions. However, its
magnetoelectric coupling polarity was found to be opposite to the earlier
consensus, which involves a phase transition between ferromagnetic and A-type
antiferromagnetic in manganites due to electrostatic doping into the
eg-orbitals by the ferroelectric bound charges. In our case, we propose a novel
yet complementary picture where the transition occurs between C-type
antiferromagnetic and ferromagnetic. The distinction between the earlier
consensus and our picture lies at the tetragonal distortion of the manganite
unit cell, resulting in an opposite magnetoelectric coupling polarity. We
support the perceived relationship between the phase transition and tuning of
Topological Hall Effect by micromagnetic simulations.
