The project is focused on verification of recent theories that THz-pumping of polar phonons can induce transient ferroelectricity or even magnetization in diamagnetic paraelectrics. The measurements will be performed on quantum paraelectrics KTaO3 and (EuSrBa)TiO3. We will also study influence of strain on lattice dynamics and magnetic exchange coupling in thin films of various transition metal monoxides with the aim to prepare strain-induced multiferroics in highly strained superlattices of MnO with other magnetic monoxides. Static and dynamic magnetoelectric coupling in various multiferroics will be also studied in radiofrequency, microwave and THz region.

The project is focused on verification of recent theories that THz-pumping of polar phonons can induce transient ferroelectricity or even magnetization in diamagnetic paraelectrics. The measurements will be performed on quantum paraelectrics KTaO₃ and (EuSrBa)TiO₃. We will also study influence of strain on lattice dynamics and magnetic exchange coupling in thin films of various transition metal monoxides with the aim to prepare strain-induced multiferroics in highly strained superlattices of MnO with other magnetic monoxides. Static and dynamic magnetoelectric coupling in various multiferroics will be also studied in radiofrequency, microwave and THz region.

Charged domain walls in ferroelectric materials are accompanied by a high density of charges screening the jump in the polarization. This causes fundamental changes in the electronic structure close to the domain wall; it was even anticipated that magnetic moments can be induced in otherwise non-magnetic materials. This effect was indeed observed in ferroelectrics containing charges e.g. due oxygen vacancies. We propose to search for magnetic properties induced by various charge carriers also in charged domain walls in ferroelectrics: this would enable us to achieve magneto-electric coupling and controlled operations thanks to the domain walls motion. To this aim, we will combine electron and scanning probe microscopies for micro-scale characterization, magnetization measurements, thermal noise and conventional impedance spectroscopy for sensing macro-scale properties, with calculations using the phenomenological Landau-Ginzburg-Devonshire theory. This will allow us to obtain a detailed picture of the electronic and magnetic structure of charged domain walls in ferroelectrics.

Using broadband dielectric and phonon spectroscopies, we will study the lattice and spin dynamics of multiferroics near their structural and magnetic phase transitions. We will investigate static and dynamic magnetoelectric couplings in multiferroics with Y- and Z-hexaferrite structures, in Ni_3-x(Co, Mn)_xTeO₆ (x = 1, 2), Mn₃WO₆, Cu₃Nb₂O₈ and AMn₇O₁₂ (A = Sr, Pb, Cd). These materials exhibit different crystalline and magnetic structures, so their magnetoelectric couplings will have different origins. Our data will allow us to explain the origin of static and dynamic magnetoelectric couplings. We will perform time-resolved THz-pump, THz probe experiments, which will allow for studying the dynamics of electromagnons and changes of magnetic structures on a sub-picosecond scale. We will also strive to achieve the first observation of a theoretically predicted phonon Zeeman effect; for this we will use EuTiO₃ which exhibits a strong spin-phonon coupling. Using THz and Raman spectroscopies, we will investigate the tuning of electromagnons frequencies in electric and magnetic field.