# Barium Titanate (BT) is tetragonal at room temperature.

# XRD, Raman and numerous other studies show that BT becomes cubic when Zirconium or tin is substituted at titanium site minimum by 20%.

# I have a question that -

Question 1. Does all the lattice sites become cubic (As XRD confirms no splitting of 002 and 200 peaks) or the tetragonal and cubic sites coexist?

In my opinion because of the lattice distortions caused by Zr or Sn all lattice set themselves in a cubic way and XRD gives a totally cubic even on 20% of substitution.

Question 2. Let us consider now it is totally cubic at RT. what will happen if i cool it to a temperature less than its curie temperature. It will show a tetragonality in its Raman and XRD but then all the sites will be tetragonal or a mixture of both will coexist?

Please share your opinions....