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Eu0.8Y0.2MnO3 has been widely studied due to its very distinctive phase diagram, where it is still poorly understood the actual ferroelectric character of the low temperature magnetic phases. In order to figure out what is the origin of the microscopic mechanisms that drive its behavior, we carried out a detailed study of the displacement currents for both different starting conditions and polarizing electric fields, and of the field dependent magnetodielectric effect in Eu0.8Y0.2MnO3 ceramics. The experimental results provide clear evidence for the existence of two dipolar systems, one stemming from an electric field-induced process, likely associated with the isovalent substitution of Eu3+ by the smaller off-center Y3+ ions at A-lattice sites, which is independent of any cooperative phenomena occurring in the system. The other dipolar system, strongly dependent on the existence of the first one, drives the polar behavior of the nonmodulated magnetic phase AFM-2, stable in the temperature range of 23–30 K, and is associated with the ferroelectric character of this phase. The magnetic field dependence of the complex dielectric constant clearly shows that the magnetodielectric effect is strongly dependent on the phase it is being considered, and provides further evidence for the ferroelectric character of the AFM-2 phase referred to above. [ABSTRACT FROM AUTHOR]

In this article, the author discusses about two experimental approaches explaining the buoyancy concept relating Newtonian mechanics with fluid mechanics which can help students in understanding of physics. He states that the increase of the value measured at the balance corresponds to the change in the water pressure at the bottom of the container, due to the increase of the free surface level of the water.

In this work, NaTaO3 ceramics are prepared by conventional mixed oxide method and NaTaO3 films are deposited by RF magnetron sputtering on Si/SiO2/TiO2/Pt substrates. The dielectric response of the obtained NaTaO3 ceramics and films is analyzed as a function of frequency and temperature. Between 1 kHz and 1 MHz, the dielectric permittivity of NaTaO3 ceramics is frequency independent and increases on cooling up to ∼324, which is the highest value ever reported for NaTaO3 ceramics. In contrast, NaTaO3 films exhibit a dielectric relaxation between ∼20 and 30 K, following the Arrhenius law with activation energy ∼51 meV and pre-exponential term ∼10-15 s and attributed to polaron hopping. [ABSTRACT FROM AUTHOR]

The effect of Sr vacancies on the behavior of strontium titanate with trivalent dopants (La3+, Gd3+, and Y3+) substituting Sr2+ ions is reported. A remarkable shift of the antiferrodistortive transition temperature Ta is revealed by Raman spectroscopy for just a small content of dopant. It is shown that a unique linear dependence of Ta versus tolerance factor is obtained when Sr-vacancies are taken into account. A vacancy size value of ∼1.54 Å is estimated, which is ∼7% larger than Sr2+ radius. This size difference enables explaining the unexpected increase of lattice parameter with increasing Bi3+ content in Sr1-1.5xBixTiO3. [ABSTRACT FROM AUTHOR]

The effect of platinum (Pt) bottom electrode texture on the tetragonality, dielectric, ferroelectric, and polarization switching response of pulsed laser deposited Ba0.8Sr0.2TiO3 (BST) thin films has been studied. The x-ray diffraction and Raman analysis revealed the higher tetragonality of BST films when they were grown on higher (111) textured Pt layer. The properties like dielectric permittivity, polarization, switching time, and leakage currents were found to be correlated to tetragonality and orientation of the BST films. The polarization current was observed to be higher in BST films on Pt epitaxial layer and it exhibits exponential dependence on the electric field. The voltage-current measurements displayed Ohmic behavior of leakage current irrespective of Pt texture for low voltages (up to 1 V), whereas at higher voltages the conduction mechanism was found to be dependent on texture selection of bottom Pt electrode. [ABSTRACT FROM AUTHOR]