E. Dul’kin

Intermediate temperature scale T ∗ in lead-based relaxor systems

Via a combination of various experimental and theoretical techniques, a peculiar, identical temperature scale

Nature of thermally stimulated acoustic emission from PbMg1/3Nb2/3O3–PbTiO3 solid solutions

{T}^{\ensuremath{\ast}}

Burns, Néel, and structural phase transitions in multiferoic Pb(Fe2/3W1/3)O3-xPbTiO3 detected by an acoustic emission

is found to exist in all complex lead-based relaxor ferroelectrics studied by us.

Structural instabilities, incommensurate modulations and P and Q phases in sodium niobate in the temperature range 300–500 K

{T}^{\ensuremath{\ast}}

Dielectric maximum temperature non-monotonic behavior in unaxial Sr0.75Ba0.25Nb2O6 relaxor seen via acoustic emission

corresponds to a nanoscale phase transition associated with random fields. Interestingly,

Acoustic emission and thermal expansion of Pb(Mg1/3Nb2/3)O3 and Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals

{T}^{\ensuremath{\ast}}

Detection of phase transitions in sodium bismuth titanate–barium titanate single crystals by acoustic emission

also exists in other oxides with extraordinary properties, such as giant magnetoresistivity or superconductivity. By analogy with such latter systems, the giant piezoelectricity related to relaxors might originate from proximity competing states effect.

Acoustic emission and nonergodic states of the electric-field-induced-phase transition of PbMg1∕3Nb2∕3O3

We discuss the nature of the thermally stimulated acoustic emission (AE) in single crystals of PbMg1/3Nb2/3O3–PbTiO3 (PMN-PT). In particular, we derive an expression describing the efficiency of AE and we discuss in this connection AE from pure PMN. We have carried out original experiments revealing the dependence of AE in PMN-PT on the electric bias fields, and we found that the AE efficiency of PMN-PT can be heavily enhanced in a certain temperature interval by applying an electric bias field.

Evidence of local anisotropic strains in relaxor ferroelectrics below intermediate temperature T* detected by acoustic emission

We investigated the ceramics samples of multiferoic solid solution of relaxor ferroelectric Pb(Fe2∕3W1∕3)O3 with ferroelectric PbTiO3 (abbreviated as PFW-xPT; x=0, 0.25, and 0.37) by means of acoustic emission (AE) method and simultaneously using the dielectric measurement below 700K. A distinct AE response has been detected at Burns temperature Td≈640–650K, where the dynamic polar clusters start to appear, at intermediate temperature of 510–520K, where the polar clusters become probably static, at ferroelectric phase transition temperatures Tc, and at Neel antiferromagnetic phase transitions. The Neel temperatures TN in ceramics were observed to be lower than in the crystals; the origin is discussed. Based on detected AE responses, we have corrected previously obtained phase diagram for PFW-xPT system.

Characteristic temperatures of PbFe1/2Nb1/2O3 ferroelectrics crystals seen via acoustic emission

The relation between the phase transition in the vicinity of 420 K discovered earlier and the formation of an incommensurate phase in the temperature range 410–460 K is established based on the X-ray, dielectric, and dilatometric studies of sodium niobate (NaNbO3) single crystals and ceramics. It is also established that this phase is characterized by temperature and temporal instabilities. Anomalies in some physical characteristics in the vicinity of 350 K are revealed. It is also shown that the thermodynamic history of the samples is important for the coexistence of the regions of the ferroelectric Q and antiferroelectric P phases in NaNbO3.