The rapid development of spintronics requires the devices
to be
flexible, to be used in wearable electronics, and controllable, to
be used with magnetoelectric (ME) structures. However, the clamping
effect inevitably leads to a decreased ME effect on the rigid substrate,
and it remains challenging to directly prepare high-quality ferroelectric
(FE) membranes on the widely used flexible substrate such as MICA
or polyimide (PI). Here, periodic wrinkle-patterned flexible (Co/Pt)5/BaTiO3 (BTO) perpendicular magnetic anisotropy
(PMA) heterostructures were prepared using the water-soluble method.
The high-quality single-crystal BTO membrane ensures that intricate
wrinkles do not fracture and a high ME coefficient is achievable.
The transferred sample that is released from the clamping effect shows
an enhanced ME effect in both in-plane and out-of-plane directions,
with the ME coefficient reaching up to 68 Oe °C–1. The ferromagnetic resonance (FMR) field of the flexible sample
can be tuned by tensile strain up to 272 Oe. The finely controlled
wrinkle shows periodic strain variations at peak and valley regions
that switch the PMA magnetic domain motion as an effective control
method. The proposed ultraflexible wrinkle sample shows great potential
for combining multiple magnetization tuning approaches, allowing it
to potentially serve as a tunable high-density 3D storage prototype.