Dipolar polarization in Ba(Ti1-xSnx)O3

The measurements of linear expansion and remanent polarization have been performed for polycrystalline samples of Ba(Ti1-xSnx)O3 (BTS-x, x = 0, 0.05, 0.10, 0.20). The results obtained from the dilatometric investigations confirm the existence of the dipolar polarization Pd below 620 K, which has been previously observed in several materials. At the temperature of para-ferroelectric phase transition a new polarization called a cooperative polarization Pk appears. This polarization together with the oriented part of dipolar polarization - Po, contribute the observed spontaneous polarization Ps. The increase of Sn substitution in BTS leads to the increase of freezing of dipolar polarization during transition to ferroelectric state.