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jahn-teller-effect
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Composition lines of the visible band of synthetic diamond
, Article Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers ; Volume 42, Issue 5 A , 2003 , Pages 2749-2751 ; 00214922 (ISSN) ; Shafiekhani, A ; Horiuchi, K ; Sharif University of Technology
Japan Society of Applied Physics
2003
Abstract
The visible band (band A) of photoluminescence spectra of high-purity synthesized diamond is analyzed by the deconvolution technique. A set of eight lines with distinct peak energies are found. The peak energy and the width of these lines were either constant or varied very slightly with temperature. The amplitude of the lines are significantly temperature dependent. The closeness of the temperature at which the amplitudes of these lines reach their minimum to the temperature at which the free-exiton emission is maximum, is an indication of the competition between these two effects
Structural, magnetic, and optical properties of zinc-and copper-substituted nickel ferrite nanocrystals
, Article Journal of Superconductivity and Novel Magnetism ; Volume 25, Issue 7 , 2012 , Pages 2443-2455 ; 15571939 (ISSN) ; Daadmehr, V ; Rezakhani, A. T ; Akbarnejad, R. H ; Gholipour, S ; Sharif University of Technology
Springer
2012
Abstract
Ferrite nanocrystals are an interesting material due to their rich physical properties. Here we add nonmagnetic dopants Zn and Cu to nickel ferrite nanocrystals, Ni1-xMxFe2O4 (0 ≤ x ≤ 1, M = Cu, Zn), and study how relevant properties of the samples are modified accordingly. Basically, these dopings cause a rearrangement of Fe +3 ions into the two preexisting octahedral and tetrahedral sites. In fact, this, we show, induces pertinent magnetic properties of the doped samples. In the case of the Cu-doping, the Jahn-Teller effect also emerges, which we identify through the Fourier Transform Infra-Red Spectroscopy of the samples. Moreover, we show an increase in the lattice parameters of the...