FINANCING CONTRACT NO: PD 133 din 20/08/2020

Code: PN-III-P1-1.1-PD-2019-0739

Project Duration (months):  24

The considerable research interest raised by ferroelectrics has been increasingly directed, in recent years, towards nanostructures, paying special attention mostly to “lead-free” materials. The nanoscale transition has become one of the engines of nowadays research since it made it possible to acquire multi-functionality in many types of materials and structures. The size-dependent electrical properties observed in ferroelectrics have been extensively investigated in un-doped BaTiO3-BT ceramics, and not to the same extent in the related solid solutions. The present project shall perform a complete investigation of the grain size effects on the structural/microstructural and macroscopic functional properties in (Ba, Sr)TiO3-BST, a BT-based solid solution.

The study will be performed by a multidisciplinary approach, involving innovative wet-chemical methods for the preparation of nanopowders and combined conventional and spark plasma sintering to obtain dense nanostructured BST ceramics of different compositions and grains scales. There are two envisaged BST compositions, in different phase states at room temperature: (i) Ba0.8Sr0.2TiO3, in the ferroelectric tetragonal state (PS≠0), and (ii) Ba0.6Sr0.4TiO3, in the paraelectric cubic state (PS=0). This research can bring major contributions to clarify the influence of the grain size effects along with interfaces/boundary – related phenomena on the type and characteristics of the ferroelectric-paraelectric phase transition and the structural, thermal, and dielectric properties of BST ceramics of various grain sizes.

The challenge is to understand how the functional properties of bulk BST ceramics are influenced by the grains size and to find the optimal characteristics for specific applications in the microelectronic industry. The results can be used as a foundation for pointing out unanswered issues regarding size-dependent and interfaces/boundary-related phenomena in BST ferroelectrics and paves the way for future improvements.

Project Domains

Main Domain     PE. PHYSICAL SCIENCES AND ENGINEERING; Main Subdomain              PE5. Synthetic Chemistry and Materials: Materials synthesis, structure-properties relations, functional and advanced materials, molecular architecture, organic chemistry; Main research area         PE5_2. Solid-state materials

Secondary Domain          PE. PHYSICAL SCIENCES AND ENGINEERING; Secondary Subdomain   PE5. Synthetic Chemistry and Materials: Materials synthesis, structure-properties relations, functional and advanced materials, molecular architecture, organic chemistry; Secondary research area               PE5_1. Structural properties of materials

Tertiary Domain                PE. PHYSICAL SCIENCES AND ENGINEERING; Tertiary Subdomain         PE4. Physical and Analytical Chemical Sciences: Analytical chemistry, chemical theory, physical chemistry/chemical physics; Tertiary research area    PE4_17. Characterization methods of materials

Keywords: ferroelectrics, micro/nanostructured ceramics, barium strontium titanate, grain-size effects, dielectric properties