Magnetic materials play a crucial role in presentdays technological advance. Smart materials such asmagnetostrictive materials exhibit both sensing andactuation behavior. Magnetostrictive sensors havevarious applications in Sonar, Aerospace design,Marine industries and several other applications. Itis well known that microstrcture of materialsdrastically affects the magnetic properties. Thepresent work is divided in two parts. Part I mainlydeals with understanding the effects ofmicrostructural modification as well assubstitutional effects by other elements such as Mnin cobalt ferrite. The results of variousprocessing parameters affecting the magnetostrictionhave been discussed. The materials were obtained bytechniques such as ceramic method and otherestablished low temperature methods of synthesis suchas combustion synthesis to get bulk and nano powdersrespectively. Part II of the work is about the effect of Fesubstitution on the magnetic and structuralproperties of lanthanum manganites.