Nanoscale free-standing magnetoelectric heteropillars

Nanocomposites with a film-on-substrate geometry usually suffer from a large clamping effect from the substrate, inhibiting the elastic-interaction-mediated "product" property such as the magnetoelectric response in piezoelectric-magnetostrictive systems. Here we report a self-assembling strategy to synthesize nanoscaled free-standing magnetoelectric heteropillars. The degree of clamping from the substrate has been greatly reduced, which is manifested by enhanced piezoelectricity and isotropic magnetic behaviors. A combination of techniques such as transmission electron microscopy, Raman spectroscopy and X-ray diffraction provide additional evidence of stress release in the as-prepared nanocomposite. Moreover, as a benefit of this unconstrained structure, we are able to observe a large magnetic-field-induced polarization change of up to 11.5% at room temperature, demonstrating its potential application in future magnetoelectronic devices at the nanoscale.