Dielectric spectra of a new relaxor ferroelectric system Ba2LnTi2Nb3O15   (Ln=La, Nd)
  New relaxor ferroelectric system has been synthesized. BLTN exhibits a smeared maximum of permittivity, characteristic of classic relaxor behaviour, with a peak shift from 185 K at 100 Hz to 300 K at 1 GHz. BNTN undergoes a first order ferroelectric phase transition at 389 K and BLNTN exhibits both a ferroelectric phase transition at 274 K and relaxor behaviour at higher temperatures. 
S. Kamba, S. Veljko, M. Kempa, M. Savinov, V. Bovtun, P. Vanek, J.   Petzelt, M.C. Stennett, I.M. Reaney, A.R. West