Magnetoelectric (ME) multiferroics are some materials that bear ferroelectric and (ferro)magnetic domains in the same phase with a coupling between them and hence prove to be novel materials showing long sought-after combination of electronic and magnetic functionalities in a single device component. As regards multiferroic oxides, offers a comprehensive range of studies regarding substitutions in these systems which has made them particularly interesting from the point of view of following their magnetic, electric and dielectric behaviour. The present Book presents the magnetic, electrical and dielectric behaviour of (i) HoCrO3 based systems and (ii) magnetoelectric composite (ME) systems of cobalt ferrite and Zr substituted barium titanate (with ~10 atomic% occupancy). The systems under study are - of substituted HoCrO3 (with substitutions being made at Ho and Cr site) and magnetoelectric (ME) composites of CoFe2O4 and BaTi0.9Zr0.1O3. Effects have been examined on the substitutions of (i) Rare earth cations like Gd3+ and Yb3+, for Ho3+ and (ii) transition metals like Fe and Mn, for Cr in HoCrO3 multiferroic system.