The present invention relates generally to polymer composites having dispersed therein both useful spinel crystal fillers and ferroelectric (and/or paraelectric) fillers wherein the composite is both light activatable and can be used as a planar capacitor material. The light activation is typically employed via a laser beam (or other light emitting device) where the material has a pattern formed thereon. Electrodes are typically formed on the material's surface after patterning is complete via electroless metal plating. These composite polymers can be used as planar capacitors embedded in printed wiring boards or in integrated circuit packages.