Ferroelectric Domains,Tensor Pairs and Magnetoelectric Polarisability Properties of Single Ferrotroiodic Crystal

Abstract

In this paper the Tensor components of the ferroelectric and Magneto electric  polarisability for the ferrotroidic crystal Pb(Mg_1/3Nb_1/3)O₃-xPbTiO₃ are calculated theoretically using group theoretical methods  at the transition temperature 5^ok, where magnetite undergoes a first order metal _insulator  transition, which lowers the crystallographic symmetry from cubic (m3m/Oh) to Rhombohedra(3m/C_3v), again this crystal changed its structure into orthorhombic(mm2/C_2v) or tetragonal structure(4mm/C_4v) at certain temps.