arXiv subjects

M. S. Prosandeeva

Publications and source records attributed to M. S. Prosandeeva.

3 recordsLinked to original sources

arXiv2005

The Significance of the Burns Temperature in Relaxor PMN

We suggest considering the Burns temperature in lead containing relaxor ferroelectrics as the temperature, at which Pb becomes off-center and nearly randomly occupies positions around the center on a sphere with the radius, which increases with the temperature decrease. The significance of the Burns temperature, in this approach, is the crossover between the soft-mode and order-disorder dynamics. The lattice parameter, birefringence and neutron scattering experiments are analyzed in the light of this model.

cond-mat.dis-nn↗

arXiv2005

Experimental and theoretical study of the influence of disorder on diffuse first-order phase transitions: NaNbO3: Gd and KTaO3: Li as examples

We consider consequences of local disorder in systems experiencing first order phase transitions. Such systems can be of rather different nature. For example, manganates showing gigantic magnetoelectric effect, doped antiferroelectrics or biomembranes. Monte-Carlo computations performed have shown that the disorder increases the temperature interval where the high- and lowtemperature phases coexist and this provides thermodynamics in the disordered systems distinct from the thermodynamics of classical homogeneous systems.

cond-mat.mtrl-sci↗

arXiv2004

Diffuse first-order phase transition in NaNbO$_3$:Gd (a report)

Dielectric permittivity measurements show that (1-x)NaNbO3-(x)Gd1/3NbO3 crystals, at $x=0.09$, exhibit a first order phase transition near 150 C which is diffuse over a wide temperature interval. The area of the ε(T) thermal hysteresis loop was found to depend both on the annealing and cooling temperatures. Optical studies in polarized light show the decrease of the domains sizes at this phase transition. The results obtained are fitted assuming the space distribution of Curie temperatures.

cond-mat.mtrl-sci↗