Colossal dielectric permittivity of BaTiO3-based nanocrystalline ceramics sintered by spark plasma sintering

摘要

In pursuit of high permittivity materials forudelectronic application, there has been a considerable interest recently in the dielectric properties of various perovskite oxides like calcium copper titanate or lanthanum doped barium titanate. When processed in a particular way, this later material present at ambient temperature and at f=ud1 kHz unusual interesting dielectric properties, a so calledud“colossal” permittivity value up to several 106 withudrelatively low dielectric losses. Moreover and contrary toudwhat is classically expected and evidenced for this type ofudmaterials, no temperature dependence is observed. Thisudbehavior is observed in nanopowders based ceramics. Anudassumption to explain the observed properties is proposed.udThese results have important technological applications,udsince these nanoceramics open a new route to theudfabrication of very thin dielectric films.