Electric or magnetic tunability of RF and microwave devices is desirable for a variety of civilian and military applications. Tremendous advances have been made in thin-film processing, in particular with metal-oxide thin films. Consequently, it has been recognized that the integration of nonlinear dielectric, ferrite, colossal magnetoresistive (CMR) ferromagnetic, and superconductor materials could revolutionize tunable devices by providing capabilities while significantly reducing size and cost. Crucial issues facing this technology concern the material properties, in particular, the loss...