Exploring the XXIII Czech-Polish Seminar and the fascinating science behind material transformations
For nearly half a century, a dedicated group of scientists has gathered every two years, alternating between the picturesque landscapes of the Czech Republic and Poland. Their mission: to unravel the mysteries of how materials transform at the most fundamental level.
The XXIII Czech-Polish Seminar on Structural and Ferroelectric Phase Transitions, held from May 21-25, 2018, in Kouty, Czech Republic, continued this proud tradition, serving as an international forum for presenting groundbreaking research, engaging in unconstrained discussions, and initiating collaborative studies 3 5 .
This biannual event, which typically brings together 100-120 participants, represents a unique blend of scientific excellence and enduring camaraderie. Approximately one-third of the attendees come from the Czech Republic, one-third from Poland, and the rest from countries across the globe 3 .
The seminar stands as a testament to the powerful scientific cooperation between the Department of Dielectrics of the Institute of Physics of the Czech Academy of Sciences in Prague and the Ferroelectric Lab of the Institute of Molecular Physics of the Polish Academy of Sciences in Poznań 5 .
Imagine a material that can spontaneously generate electricity when squeezed, remember its electrical history, and switch its internal polarity with an external electric field. These are ferroelectric materials, and they form a core focus of the research presented at the seminar.
Unlike typical insulators, ferroelectrics possess a built-in electric polarization that can be reversed by applying an external electric field. This unique property makes them incredibly valuable for a wide range of technologies.
A key theme explored throughout the seminar was the nucleation-and-growth mechanism that governs solid-state phase transitions 4 . This process explains how materials transform from one phase to another, not instantaneously, but through a fascinating sequence of events.
This mechanism provides a crucial explanation for one of the defining characteristics of ferroelectric materials: hysteresis. This hysteresis is not a flaw but a fundamental feature arising from the nucleation-and-growth process, and it is essential for applications like ferroelectric memory 4 .
Retains data even when power is removed
Ultrasonic systems that see inside the human body
Detect minute changes in pressure or temperature
Energy-efficient devices that manipulate light
The XXIII Czech-Polish Seminar covered an impressive range of topics, reflecting the vibrant diversity of modern materials science 1 .
The translation of fundamental research into real-world technologies.
To illustrate the type of research presented at the seminar, let's examine a representative experimental study on ferroelectric materials similar to those discussed at such gatherings. One fascinating line of inquiry focuses on enhancing the properties of classic ferroelectric materials through strategic chemical modifications.
Barium titanate (BaTiO₃) is one of the most thoroughly studied ferroelectric materials, famous for its successive phase transitions from a high-temperature cubic structure to tetragonal, orthorhombic, and finally rhombohedral phases upon cooling 7 .
Despite its widespread use in piezoelectric ceramics, high-permittivity dielectrics, and nonlinear optical devices, BaTiO₃ presents a significant challenge: the difficulty of growing large, high-quality single crystals 7 .
Researchers have discovered that substituting atoms in the crystal lattice can overcome this limitation and dramatically improve the material's properties. In particular, replacing some of the barium ions with smaller calcium ions (Ca²⁺) creates Ba₁₋ₓCaₓTiO₃ (often abbreviated BCTO), a modified material that exhibits "giant electromechanical responses" 7 .
The process of creating and analyzing these advanced materials involves several meticulous steps:
Researchers mix high-purity powders of BaCO₃, CaCO₃, and TiO₂ in specific molar ratios. The mixture is sintered at 1473 K (approximately 1200°C) for 18 hours in a nitrogen gas environment to prevent oxidation.
The sintered material is ground into a fine powder, pressed into cylindrical shapes, and then grown into single crystals using the optical floating-zone method. This technique involves melting the powder in a high-temperature furnace and slowly recrystallizing it at a controlled rate of 8 mm/hour under nitrogen gas 7 .
The resulting crystals are subjected to a battery of tests including X-ray diffraction, dielectric spectroscopy, and Brillouin scattering 7 .
| Property | Effect of Calcium |
|---|---|
| Crystal Growth | Enables growth of larger single crystals |
| Phase Stability | Stabilizes the tetragonal ferroelectric phase |
| Transition Character | Creates diffuse transitions |
| Electromechanical Response | Leads to giant electromechanical responses |
Studies on calcium-substituted barium titanate have revealed fascinating phenomena. The random substitution of barium ions with calcium creates what scientists call "compositional disorder" 7 . This disorder spreads out the phase transition over a broader temperature range, giving it a "diffuse" character rather than occurring abruptly at a single temperature.
The calcium ions act as stabilizers for the tetragonal phase of the crystal, which is responsible for the strong ferroelectric and piezoelectric properties. This stabilization enhances the material's performance, making it more suitable for practical applications.
Improved Crystal Growth
Enhanced Phase Stability
Giant Electromechanical Response
Practical Applications
Which combine ferroelectric and magnetic properties, are opening possibilities for entirely new types of electronic devices that can be controlled by either electric or magnetic fields.
With their exceptionally high electromechanical responses, are revolutionizing medical ultrasound technology and precision actuators.
Are enabling the next generation of low-power, non-volatile computer memory that retains data even when power is disconnected.
Explores how ferroelectric properties change at the nanoscale, potentially leading to ultra-dense memory storage and miniature electronic components.
The XXIII Czech-Polish Seminar on Structural and Ferroelectric Phase Transitions represented both a celebration of a rich scientific heritage and a looking-forward to an exciting future.
The research presented—from tuned barium titanate crystals to novel two-dimensional materials—demonstrates the vibrant health of a field that continues to reveal fundamental truths about materials while enabling transformative technologies.
As the seminar series continues with future meetings, such as the XXIV seminar held in Harrachov, Czech Republic, in 2022 , this unique collaborative platform will undoubtedly continue to drive innovation at the intersection of physics, materials science, and engineering.
Years of Scientific Collaboration
Seminars Held
Average Participants