Strain-Induced Dielectric Enhancement in AlN-Based Multiferroic Layered Structure

In this work, a lead-free magnetoelectric composite of AlN (300 nm)/NiMnIn (300 nm) structure has been fabricated using DC magnetron sputtering. The AlN-based multilayered structure on NiMnIn layer exhibits a (002) oriented wurtzite growth with columnar structure perpendicular to the substrate. The layered structure has low level of leakage current which is beneficial for reducing dielectric loses. The Piezoresponse of the fabricated multilayered structure is measured by Piezo force microscopy and found to be about 5.17 pm/V. The magnetization versus temperature graph shows a martensite transformation at about 273–295 K. The stain produced during this transformation is visualized in terms of variation in the dielectric constant of the fabricated heterostructure. The transformation region is also verified by resistance versus temperature behavior. Such AlN-based multilayered structures with enhanced dielectric constant are useful for futuristic magnetic field sensing and Microelectromechanical system-based device applications.