Executive Summary : | The increasing demand for spintronics devices with higher energy efficiency and storage capacity has led to research on new 'type-II' multiferroic and magnetodielectric (ME) materials. However, materials with substantial ME coupling at higher critical temperatures are rare, requiring more effort to discover new materials with enhanced ME properties. Studying non-collinear and non-coplanar magnets, including helical, spiral, and cycloidal spin systems, can help unravel new ME materials. These complex spin orderings are mostly observed at very low temperatures (TN<20 K), making it crucial to look for magnets with higher TN. The proposed work focuses on three magnets: Ni₂ScSbO₆ (helical ordering below TN~60 K), Sr₂FeO₄ (elliptical cycloidal spiral ordering below TN~56 K), and Co₅TeO₈ (spiral ordering below TN~45 K). These systems have high possibilities for emerging as new spin-driven multiferroic candidates due to their special spin structures and ME coupling at higher critical temperatures. A comprehensive study deciphering the electric and structural properties of these systems is still missing. The project will conduct a detailed study of the dielectric, magnetodielectric, and pyroelectric properties of these systems in their polycrystalline and single crystalline forms to uncover ferroelectricity near TN. Temperature-dependent high resolution synchrotron X-ray diffraction, Raman spectroscopy measurements, and density functional theory calculations will be performed to better understand the underlying origin of ME properties. The possibility of switching the magnetic state by applying an electric field opens up numerous opportunities for spintronic applications. The project will also prepare bi-layer thin films using the proposed antiferromagnetic (AFM) ME materials and a ferromagnetic (FM) system La₂NiMnO₆ to investigate the electric field control of exchange bias effect. |