Electrical and Mechanical Manipulation of Ferromagnetic Properties in Polycrystalline Nickel Thin Film

The ferromagnetic properties of a 35 nm polycrystalline nickel thin film deposited on a single-crystal, optical, ferroelectric lithium niobate substrate are magnetoelectrically tunable. The coercive field of the nickel film, which has low magnetocrystalline anisotropy and appropriate magnetoelasticity, changes by about 80% owing to the anisotropic strain produced by the substrate. In addition, mechanical strain changes the coercive field by about 260% and increases the normalized remanence \bm
M
_\bm
r
/\bm
M
_\bm
s
from 0.3 to 1.0. This giant tunability would be achievable by combining polycrystalline Ni thin film with a ferroelectric substrate having large anisotropic piezoelectric coefficients.