Electron paramagnetic resonance measurements near the tricritical point in BaTiO3
نویسندگان
چکیده
We report electron paramagnetic resonance measurements on BaTiO3, containing a dilute impurity of Fe , in its ferroelectric phase over a range of pressure and temperature near the paraelectric-ferroelectric phase transition line. We have developed an algorithm to analyze the data, allowing us to determine the values of the crystal field parameters and their temperature and pressure dependence required to reproduce the measured spectra. Then, using the Landau free energy expansion to sixth order in the order parameter and noting that the tetragonal distortion field D is proportional to the square of the order parameter, we determine the Landau parameters and get a value for the tricritical point for BaTiO3.
منابع مشابه
MAGNETISATION AND ELECTRON SPIN RESONANCE STUDIES OF TETRAHEDRAL AMORPHOUS CARBON
The magnetisation and electron spin resonance (ESR) spectrum of two specimens of tetrahedral amorphous carbon (ta-C), deposited from a filtered cathodic arc, were measured over a wide temperature range. The magnetisation was found to consist of superparamagnetic, paramagnetic and diamagnetic contributions. The superparamagnetic contribution resembled that recently found in carbon prepared from ...
متن کاملDielectric and polarization measurements on BaTiO3 at high pressures to the tricritical point.
Dielectric and polarization measurements were made on single crystal BaTi03 in a hydrostatic medium to 38 kbar. The nature of the ferroelectric phase transition is observed to go from first to second order near 35 kbar and —40 C. The pressure —temperature —electric-field phase diagram of BaTi03 is measured. The tricritical point is indicated in this part of the phase diagram by a change in shap...
متن کاملEPR studies of Cd substituted Mn Zn nanoferrites
Nanoparticles of Mn0.5Zn0.5-xCdxFe2O4 with x varying from x = 0.0 to 0.3 were prepared by wet chemical co-precipitation method. The structural and magnetic properties were studied by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and Electron Paramagnetic Resonance (EPR) technique. ...
متن کاملEPR studies of Cd substituted Mn Zn nanoferrites
Nanoparticles of Mn0.5Zn0.5-xCdxFe2O4 with x varying from x = 0.0 to 0.3 were prepared by wet chemical co-precipitation method. The structural and magnetic properties were studied by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and Electron Paramagnetic Resonance (EPR) technique. ...
متن کاملDemystifying EPR: A Rookie Guide to the Application of Electron Paramagnetic Resonance Spectroscopy on Biomolecules
Electron Paramagnetic Resonance (EPR) spectroscopy, also known as Electron Spin Resonance(ESR) especially among physicists, is a strong and versatile spectroscopic method forinvestigation of paramagnetic systems, i.e. systems like free radicals and most transition metalions, which have unpaired electrons. The sensitivity and selectivity of EPR are notable andintriguing as compared to other spec...
متن کامل