Enhanced energy-storage and magnetoelectric properties of Ba0.95La0.05Zr0.4Ti0.6O3/CoFe2O4 multilayer thin films

Abstract

Multifunctional thin films and devices have gained much interest in both scientific and industrial research for futuristic multifunctional micro- and nano-device applications. Here, we report the development of a multi-layer structure based on relaxor-ferroelectric Ba0.95La0.05Zr0.4Ti0.6O3 (BLZT) and ferrimagnetic CoFe2O4 (CFO) ([BLZT/CFO]3/BLZT or BLZT/CFO) thin-films on Si substrates for enhanced energy-storage density and magnetic properties. An ultrahigh recoverable energy-storage density (Ur) of 137.6 J/cm3 together with an energy efficiency of 76.6 % are achieved for the BLZT/CFO multi-layer, owing to the enhanced breakdown-strength (EBD) of 8.0 MV/cm (BLZT single-layer has an Ur value of 84.7 J/cm3 at EBD of 5.5 MV/cm). Moreover, the saturation magnetization of CFO layers in the BLZT/CFO multi-layer significantly increases from 239.2 kA/m to 276.4 kA/m. This enhancement can be attributed to the enlarged magnetic domains in CFO layers, which follow the piezoelectric domain switching in the BLZT layers induced by applying a dc-bias voltage. These remarkable performances indicate that the BLZT/CFO multi-layer is a promising candidate for multifunctional energy storage and magnetoelectric device applications.