Adaptive ferroelectric states in systems with low domain wall energy: Tetragonal microdomains

Abstract

Ferroelectric and ferroelastic phases with very low domain wall energies have been shown to form miniaturized microdomain structures. A theory of an adaptive ferroelectric phase has been developed to predict the microdomain-averaged crystal lattice parameters of this structurally inhomogeneous state. The theory is an extension of conventional martensite theory, applied to ferroelectric systems with very low domain wall energies. The case of ferroelectric microdomains of tetragonal symmetry is considered. It is shown for such a case that a nanoscale coherent mixture of microdomains can be interpreted as an adaptive ferroelectric phase, whose microdomain-averaged crystal lattice is monoclinic. The crystal lattice parameters of this monoclinic phase are self-adjusting parameters, which minimize the transformation stress. Self-adjustment is achieved by application of the invariant plane strain to the parent cubic lattice, and the value of the self-adjusted parameters is a linear superposition of the lattice constants of the parent and product phases. Experimental investigations of Pb(Mg1/3Nb2/3)O3–PbTiO3 and Pb(Zn1/3Nb2/3)O3–PbTiO3 single crystals confirm many of the predictions of this theory.

Nonlinear stress-strain behavior and stress-induced phase transitions in soft Pb(Zr1−xTix)OSeo1, Franzbach2, Koruza3 et al. 2013Phys. Rev. B496261View full textAdd to dashboardCite

“…17,18 The reduction of domain wall energies and the resulting nanometer scale domains has been predicted by Jin et al, who applied the adaptive state theory of martensites to ferroelectrics. 19,20 As the composition is moved further from the MPB in either the tetragonal or rhombohedral direction there is a corresponding increase in the coercive stress and a decrease in the remanent strain. Cao and Evans 5 investigated the stress-strain behaviors for both hard and soft doped PZT, showing that the coercive stress of an acceptor (hard) doped material is larger than that of a donor (soft) doped.…”

Temperature dependence of the direct piezoelectric effect in relaxor-ferroelectric single crystals: Intrinsic and extrinsic contributions

“…41͒ are well known to exhibit fine domain structures due to a low domain wall energy. 42 However, crystals with compositions close to the MPB, such as PZN-8PT, 41,43 exhibit ͑ferroelastic͒ domain sizes larger than 50 m in such compositions, the intrinsic ͑lattice͒ contribution might be expected to dominate.…”

“…Another possible explanation for the giant piezoelectric response of PMN-xPT and PZN-xPT is the "adaptive phase" 44 model recently proposed by Jin et al, 42 Viehland, 45 and Wang. 46 Noting the similarities 47 between relaxorferroelectrics and martensites the authors propose a model based on the fine-scale twinning of tetragonal ͑or rhombohedral͒ domains.…”

Three intrinsic relationships of lattice parameters between intermediate monoclinicMCand tetragonal phases in ferroelectricPb[(Wang1 2006Phys. Rev. B781200View full textAdd to dashboardCite

“…Khachaturyan and co-workers [29][30][31] recently proposed an adaptive ferroelectric phase theory to explain the behaviors of intermediate monoclinic phases in PMN-xPT and PZNxPT. According to this theory, the monoclinic phase is a mixed state of miniaturized domains of the conventional ferroelectric phase, which is inhomogeneous on the nanos-cale while homogeneous on the macroscale.…”