Vislielākais burtu izmērs
Lielāks burtu izmērs
Burtu standarta izmērs
Achievements 2010 - 2017
Last Update
20.02.2018

A new relaxor family Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 with the largest known range of relaxor behavior up to now is synthe­sized and studied for the first time:

  • High value ECE at field-induced phase transitions in compositions with weak stability relaxor state,
  • Relation of local energy landscape and stability of ferroelectric state in appearance of relaxor state,
  • New approach (instead of Vogel-Fulcher law),
  • Evaluation of Burns temperature.

Phase diagram of Na1/2Bi1/2TiO3-BaTiO3 solid solutions above morphotropic phase boundary:

  • Three types of concentration range with different nature of phase transition have been found,
  • High tetragonality of lattice with increasing concentration of Na1/2Bi1/2TiO3 is found,
  • Contribution to interpretation of phase transitions in pure Na1/2Bi1/2TiO3.

Dependence of electrocaloric effect on polarisation in relaxor state is determined. Maxwell relations are examined as method for indirect determination of electrocaloric effect.

The Effects of 3d Admixtures on Properties of Ferroelectric PLZT8/65/35 Ceramics:

  • Admixtures may ameliorate as well as restrain relaxor characteristics,
  • Mn, Fe, Co, Ni, and Cu dopants are related to several competing factors affecting polarization: Jahn-Teller effect, change of the concentration and orientation of polar nano-regions, the Maxwell-Wagner polarization, change of the concentration of vacancies in A and/or O sub-lattices.

Characteristic bimodal grain morphology is found in NBT-based solid solutions, which is related with anomalous grain growth mechanism. The role of Bi-nonstoichiometry on depressing of this mechanism is clarified. The possibility to vary content of Bi in NBT is very restricted. Lanthanides (Er, Yb) efficiently push out Bi from A-sites of ABO3 perovskite lattice.

Improved density of potassium-sodium niobate solid solution based ferroelectric ceramics using a wide variety of oxides as sintering-promoting additives. Addition of manganese dioxide (MnO2) promotes densification as well as improves dielectric, ferroelectric and piezoelectric properties.