Condensed Matter Physics Seminar
X-Ray Study of the Ferroelectric [Ba0.6Sr0.4] [(YTa)0.03Ti0.94]O3
UConn Physics Department
We have studied the system [Ba0.6Sr0.4] [(YTa)0.03Ti0.94]O3, as produced using two different sintering temperatures. It was shown by others that for a sample sintered at 1550 degrees Celcius the material is a relaxor, whereas for the same composition produced with sintering temperature of 1600 degrees Celcius the sample is a normal ferroelectric. We have employed analysis of x-ray diffraction peak broadening, Ti K edge x-ray near edge spectroscopy, and extended x-ray absorption edge fine structure spectroscopy of Ta and Y sites in our study. We find that the 1550 degrees Celsius sinter sample has over double the lattice strain as does the 1600 degrees Celsius sample. For the lower temperature sinter material, both Ta and Y go to sites substitutional for Ti in the lattice, with a significant expansion (contraction) of the local perovskite structure abo ut Y (Ta) dopants. Thus, with only three percent B site addition of Y and Ta dopants, there is a strain associated relaxor behavior produced in a bulk sample. For the higher temperature sinter specimen, there is a marked change in the average Y environment relative to the lower temperature sinter sample.
*) P.Shanthakumar, M. Balasubramanian, D.M. Pease, A.I. Frenkel, D.M. Potrepka, V.Kraizman, J.I. Budnick , and W.A. Hines
Thursday, March 1, 2007
Gant Science Complex
(The seminar is followed by coffee/tea, cookies, and an informal discussions.)