Strong Magnetoelectric Effects of 2–2 Composites Made of AlN Films Grown by Plasma-Enhanced Atomic Layer Deposition on Magnetostrictive Foils for Energy Harvesting Applications

Abstract

This work presents a novel process of magnetoelectric (ME) stacks composed of a highly (002)-oriented aluminum nitride (AlN) film grown by plasma-enhanced atomic layer deposition (PEALD) on magnetostrictive nickel, iron, and cobalt foils. We report an efficient methodology to process high quality piezoelectric AlN films by PEALD at low temperatures. The effective transverse piezoelectric coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$e_{31,f}$</tex> was evaluated to be 0.37 C/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for the highly (002)-oriented AlN film. Moreover, by the conformal coating obtained by PEALD, a strong ME coupling of 2.8 V.cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> . Oe <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> is obtained out of resonance on 2–2 composites of a (002)-oriented AlN film on nickel. This ME device could open a novel way for energy harvesting of microsystems.