Giant dielectric permittivity was observed in La-modified $\mathrm{PbTiO}{}_3$ (PLT) with $A$-site vacancy. The observed values of PLT with $A$-site vacancy are 1 order of magnitude larger than those of relaxor ferroelectrics. The giant relative dielectric permittivity, coupled with a low dielectric loss $\left(\tan \delta \approx 0.03\right)$ of the PLT, potentially makes it one of the most promising materials for numerous modern technological applications.

• Received 27 September 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.3404