Investigation on the dielectric properties of CaCu_3Ti_(4+x)O_(12+2x)

摘要

Investigation on the dielectric properties of CaCu_3Ti_(4+x)O_(12+2x) was carried out when x was altered in the range from -0.5 to 0.5. For x = -0.5, it was found through XRD that besides primary CCTO phase, there are also CuO and CaTiO_3 phases. For x = 0.5, additional TiO_2 was found besides dominating CCTO phase. When x increases from -0.5 to 0.5, it was found that dielectric constant decreases, varistor voltage and non-linear coefficient increase while the dielelctric loss decreases. According to IBLC theory, it is suggested that the change of the grain boundary structure results in different barrier height and surface state when x changes.