A study of the interatomic interaction in oxide spinel MnCr2O4

Phonon Spectra Near Metal-Insulator Phase Transition in Li_{1+x}ti_{2-X}o_{4} System

“…A simple short-range force constant model, as was shown in papers [5][6][7][8], in spinel cases gives the similar frequencies for zone centre vibrations and Raman data. The consideration of a long-range Coulomb interatomic interaction may reduce the existing difference.…”

“…The simple force constant models are widely used in studying the phonons in spinel type oxides, sulphides and selenides [5,6]. Lattice dynamic calculations of inverse spinels had been performed in [7].…”

Study of Phonons in Superconducting Oxide Spinels (Li, Mg)1+xTi2-xO4

“…It is clear from Table 1 that (i) similar to other oxide spinels [12,13] the interatomic interaction a 2 (Ti±O) of (Li, Mg) 1x Ti 2Àx O 4 also dominates the other interatomic interactions, as octahedral bonding (Ti±O, ionic) is stronger than tetrahedral bonding (Li±O, covalent) [14]. Table 2 alongwith the observed Raman measurements [4] and phonons as calculated semi-empirically by Oda et al [5].…”

“…The present calculation is carried out by assuming the system Li 1x Ti 2Àx O 4 at x > 0 and Li 1Ày Mg y Ti 2 O 4 at y > 0, to be of ideal spinel structure. It has been observed that the Ramen A 1g and E g modes depend only on X ions in AB 2 X 4 spinels [12,13] and hence from the study of Raman modes of other oxide spinels [12,13], it has been inferred that for Li 1x Ti 2Àx O 4 and (Li,Mg) 1x Ti 2Àx O 4 the A 1g and E g modes should have a value of 628 and 429 cm À1 , respectively. The renormalized zone centre phonon frequencies obtained by semi-empirical treatment of Oda et al [5] has been used for infrared active F 1u modes.…”

Fabrication of Spinel Coating on Hp40 Alloy and Its Inhibition Effect on Catalytic Coking During Thermal Cracking of Light Naphtha

“…The strongest peak at around 685 cm -1 can be assigned to the A 1g mode generated by the bonds in octahedral Cr 3+ O 6 , while the peaks at 511 cm -1 and 600 cm -1 correspond to F 2g and E g symmetries (Chen et al, 2007). As reported previously (Chen et al, 2007;Gupta et al, 1993;Bao et al, 2016;Proy et al, 2014) Before characterizing the cross-section of the spinel coating, the sample after thermal oxidation was coated with a Ni-layer by chemical plating to protect the coatings. Figure 6 shows the SEM photograph and EDS maps of the cross-section of the spinel coating.…”