First order reversal curves diagrams for describing ferroelectric switching characteristics

First Order Reversal Curves (FORC) are polarization-field dependences described between saturation field Esat and a variable reversal field Er∈(-Esat, Esat). The FORC diagrams were proposed to describe some characteristics of the switching process in ferroelectrics. The approach is related to the Preisach model which considers the distribution of the elementary switchable units over their coercive and bias fields. The influence of the anisotropic porosity in Pb(Zr,Ti)O3 bulk ceramics on the FORC distributions demonstrated the existence of a positive/negative bias as a result of the confinement induced by anisotropy. The reducing of grain size in Ba(Zr,Ti)O3 ceramics causes an increase of the ratio of the reversible/irreversible components of the polarization on the FORC distribution indicating the tendency of system towards the superparaelectric state. The FORC method demonstrates to provide a kind of ‘fingerprinting’ of various types of switching characteristics in ferroic systems