Enhancement of dielectric performance upto GHz of the composites with polymer encapsulated hybrid BaTiO 3 –Cu as fillers: multiple interfacial polarizations playing a key role

Cu nanoparticles with diameters of 15–25 nm were grown discretely on the surface of BaTiO 3 (about 100 nm) via a hydrothermal method, and a polyethylene glycol 4000 (PEG-4000) layer was coated on the surface of the obtained BT–Cu hybrid particles.