  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.
