The Behavior of Ferroelectric Instability in the Perovskite SrTiO_3 With Doping Trivalent Ions Sc~(3+), In~(3+), La~(3+), Bi~(3+)

摘要

In the framework of generalized Gordon-Kim model the vibration frequencies of instable ferroelectric and antiferrodistortive modes, as well as energy dependencies on ion's displacement amplitudes by eigenvectors of these modes in solid solutions Sr_(1-x)Ti_(1-x/4)□_(x/4)O_3 with A - Sc~(3+), In~(3+), La~(3+), Bi~(3+) were calculated. Applicability of virtual crystal approximation for heterovalent substitution is discussed. For solid solutions with In~(3+) and La~(3+) for x = 0.25 concentration the possibility of rotation of spontaneous polarization vector was shown.