Exploration of artificial multiferroic thin-film heterostructures using composition spreads

Abstract
We have fabricated a series of composition spreads consisting of ferroelectric BaTiO 3 and piezomagnetic CoFe 2 O 4 layers of varying thicknesses modulated at nanometer level in order to explore artificial magnetoelectricthin-filmheterostructures. Scanning microwavemicroscopy and scanning superconducting quantum interference device microscopy were used to map the dielectric and magnetic properties as a function of continuously changing average composition across the spreads, respectively. Compositions in the middle of the spreads were found to exhibit ferromagnetism while displaying a dielectric constant as high as ≈120.