Synthesis of multifunctional multiferroic materials from metalorganics

Recent developments in the synthesis of multiferroic materials from metalorganics are reviewed. Single-phase multiferroics have weak coupling among ferroic properties. Heterostructures are more promising for device applications since the coupling in such structures is many orders of magnitude stronger. These heterostructures also offer more degrees of freedom such as composition, microstructure and orientation for optimized coupling. Two major deposition techniques are discussed: (i) metalorganic chemical vapor deposition (MOCVD), and (ii) chemical solution deposition (CSD). These techniques are versatile and economical for deposition of the mentioned structures. In MOCVD the film growth is continuous, whereas, CSD is a multi-step process that involves coating using suitable precursor solution followed by annealing in appropriate ambient, and the desired thickness is obtained by repeating these steps. The desired properties of metalorganic precursors suitable for use in these techniques are outlined. In the case of MOCVD, different precursor delivery methods for liquid and solid precursors are also presented as they are equally important. Recent efforts on fabrication of single-phase multiferroics and improvements in properties of single-phase materials through doping/substitution using MOCVD and CSD are reviewed. Formation and synthesis of multifunctional multiferroic composites and heterostructures using these techniques is an area that is still much to be explored.