In the past decades, there is a growing interest in the design and synthesis of composite microspheres with a dielectric solid sphere (e.g., silica, polystyrene) covered by metallic and their corresponding metal oxides shell, such as copper[1], gold[2], silver[3,4], iron oxide[5], zinc oxide[6,7], titanium oxide[8,9] and zirconium dioxide[10]. Such materials may exhibit a few unique electrical,...
