Synthesis of Coaxial CoFe2O4 - (K0.5Na0.5 )NbO3 Nanotubes by Sol-gel Technique Using Inexpensive Templates

摘要

Magnetoelectric (ME) coupling, one of the most intriguing aspects of multiferroics, may arise directly between two or more ferroic orders as in single phase multiferroics or indirectly via strain. Strain intermediate ME coupling requires intimate contact between ferromagnetic (magnetostrictive) and ferroelectric (piezoelectric) materials in the form of composites, epitaxial heterostructures or laminates. Coaxial 1-D nanocomposite structures are proved to have large interfacial contact, enhanced strain effect and heteroepitaxy compared to thin film multilayers. In this work we report the synthesis of a novel core shell CFO/KNN nanotubes by a modified template based sol-gel method. Potassium sodium niobate (KNN) is a promising lead free piezoelectric candidate with outstanding properties such as high Curie temperature (Tc～ 400 °C), considerable d33 (300-400 pC/N)and high electromechanical coupling coefficients. The flexibility of 1-D niobate based perovskite structures were proved to be feasible for self powering nanodevices that harvests its operating energy from the environment. Enhanced magneto crystalline anisotropy and high Piezo-magnetic coupling coefficient (～1)of CFO is also make them favorable for getting good ME response in heterostructure forms. Hence multilayered 1-D nanostructures using CFO and KNN were fabricated by sol-gel method using commercially available AAO template and an inexpensive(PES) membrane.