Resumen de Preparation, characterization and temperature-dependent photoluminescence in Ca_(0.90)Sr_(0.10)RuO_(3) compound
A. Quiroz, M. Abatal, E. Chavira, V. García Vázquez, E. Marinero, M. Nishioka
We report the Ca_(0.90)Sr_(0.10)RuO_(3) compound synthesized by solid-state reaction method at ambient pressure using temperatures between 700 and 800 ◦C in air. By X-ray powder diffraction (XRD), we determine a solid solution until Ca_(0.85)Sr_(0.15)RuO_(3) compound. Scanning electron microscopy (SEM) indicates than the particle size varies between 0.422 and 1.598 µm. The resistance measurement, as a function of temperature measurement from 10 to 300 K for Ca_(0.90)Sr_(0.10)RuO_(3) compound shows a metallic behavior. Finally, photoluminescence (PL) and its temperature dependence of Ca_(0.90)Sr_(0.10)RuO_(3) compound in the temperature range 6.7-296 K were measured. It was observed than the main broad band centered at ∼ 1.73 eV with the shoulders at ∼ 1.38 eV and ∼ 2.05 eV exists in the entire temperature range. It can be well fitted by three Gaussian curves B_(1), B_(2) and B_(3), centered at ∼ 1.38, ∼ 1.73 and ∼ 2.05 eV, respectively. The transitions identified as B_(1) and B_(2) are studied with temperature. The photoluminescence mechanics for Ca_(0.90)Sr_(0.10)RuO_(3) compound are presented based on the electronic structures formed by the interactions among spin, charge and lattice, in which B_(1) was identified with the charge transfer excitation of an electron from the lower Jahn-Teller split e_(g) level of a Ru^(3+) ion to the e_(g) level of an adjacent Ru^(4+) ion, B_(2) was assigned to the transition between the spin up and spin down e_(g) bands separated by Hund’s coupling energy E_(j) , whereas B_(3) is attributed to the transition, determined by the crystal field energy E_(c) between a t_(2g) core electron of Ru^(3+) to the spin up e_(g) bands of Ru^(4+) by a dipole allowed charge transfer process.
