Magnetic phase diagram and structural separation of La0.7(Ca1?ySry)0.3MnO3 thin films

The structural, magnetic, and transport properties of La0.7(Ca1?ySry)0.3MnO3 films, deposited on a LaAlO3?(001) single crystalline substrate by rf-magnetron sputtering using “soft” (or powder) targets, have been investigated. It was found that at 0.3 ? y ? 0.5 both the rhombohedral (R3c) and the orthorhombic (Pnma) crystal phases in the form of...

Enhancing the charge ordering temperature in thin films of Pr0.5Ca0.5MnO3 by strain

We report the effects of biaxial strain on the charge ordering temperature Tco of the mixed-valent manganite perovskite oxide Pr0.5Ca0.5MnO3. Thin films were grown on SrTiO3, which has a 1.3% larger in-plane lattice parameter. Other substrates were used for comparison. Transport measurements combined with data from electron microscopy show that...

Direct hole and delayed electron capture on a picosecond timescale by Eu2+ centers in CaGa2S4 monitored by synchroscan with horizontal blanking

A Eu2+ concentration and temperature dependent energy transfer study from the host lattice to Eu2+ luminescence centers in Ca(1–x)EuxGa2S4 (x = 0.001 to 0.05) was performed with a special streak camera that combines the high timing resolution of a conventional synchroscan operation (<2 ps) with the ability to study long lived states (10?ns???1...

Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra

The dehydrogenation enthalpies of Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4 have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski’s direct method. The dehydrogenation of Ca(AlH4)2 is exothermic, indicating...

Mechanism of Persistent Luminescence in Eu2+ and Dy3+ Codoped Aluminate and Silicate Compounds

A mechanism of persistent luminescence that was proposed in 1996 for SrAl2O4:Eu2+;Dy3+ has been widely adopted to explain afterglow in many Eu2+ and Dy3+ codoped aluminates and silicates. The mechanism involves the thermally activated release of a hole from Eu2+ in its excited 5d state to the valence band which is subsequently trapped by Dy3+....