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Basics of Raman spectroscopy and applications to metal oxides

Basic principles of Raman spectroscopy (RS) will be explained and related to the other spectroscopy techniques. The selection rules for Raman scattering will be mentioned with the short explanation of physical background (avoiding tedious formalism). The main specific data that can be accomplished by the technique will be discussed, in contrast or in synergy with the other main characterization techniques. Typical experimental set up of dispersive Raman spectrometer will be explained and related to the Fourier transform Raman instruments. Specific conditions of the recording Raman spectra necessary to achieve the reliable results will be clarified including the excitation lines and sample arrangement. The preparation of the samples for RS and some limits of the technique will be also considered. Raman instrumentation in our laboratory comprises high class Raman spectrometer Jobin Yvon T64000 that is triple dispersive instruments and excitation by Coherent Inova Ar ion laser operated at 514 or 488 nm. The experimental possibilities including the additional instrumentation will be described. High and low temperature chamber “Linkam” working in temperature range 77 to 773 K, and “Leitz” high-temperature cell operating in temperature range 473 to 1773 K for work in micro-Raman set up will be revealed. The work in macro chamber and the cryostats that can be attached will be shortly mentioned (He close circuit cryostat operating from 10 K to room temperature and cryostat operating form 77 to 573 K). The applications of the Raman spectroscopy as one of the powerful methods for solving the problems in materials science will be illustrated with the accent to the metal oxides including ferroelectric and multiferroic materials. The examples from different own research topics will be shown for illustration. The crystal structure and mechanism of phase transitions and solid state reactions in mechanochemically treated metal oxides elucidated by combination of the RS results with XRD and TEM results. The observation and the recognition of the luminescence lines in the Raman spectrum will be shown at the example of Y2O3 doped with rear earth elements. The use of RS for investigation of the amorphous and nearly amorphous materials with short range ordering will be shortly mentioned as well as the application and limits of RS for the study of the nanostructures.

Raman spectroscopy; metal oxides; ferroelectrics

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