Raman scattering study of the spin ladder compound Sr14Cu24O41+δ

Abstract

The spin ladder compounds Sr14Cu24O41+δ were synthesized by conventional solid state reaction method with subsequent annealing at 400, 500, 600, 800 and 900 ℃, respectively. The energy dispersive spectroscope (EDS) measurement confirms that the content of oxygen in the samples decreases with the increasing of annealing temperature. The measurement of magnetic susceptibility reveals that the sample annealing at 600 ℃ has the largest number of dimers. The measurement of Raman spectrum shows some new Raman vibrational features. Corresponding to δ>0 or δα=cl/cc is near the minimal value 10/7 and the Cu—O bond has relatively long length.

Physical meaning of conductivity spectra for ZnO ceramics

“…The defect structure, especially the intrinsic defect structure of ZnO has been investigated widely and deeply, of which the most convenient method is developed by dielectric spectroscopy. [11,12] This method is very similar to our method here. If we transform this figure of σ ′ -T into a figure of ε ′′ -f at different temperatures, the dielectric loss peaks are sharper, as shown in Fig.…”

“…According to Refs. [11] and [12], the two loss peaks in Fig. 4 come from the electronic trap relaxation process of the intrinsic point defects of ZnO.…”

“…Once the Schottky barrier height and defect structure of ZnO have been obtained from the conductivity spectra, more accurate theoretical results about the electronic structure at the grainboundary will be obtained. [12] 0. The sharp dielectric loss peaks are attributed to electronic trap relaxation of zinc interstitial and oxygen vacancy, respectively.…”

“…The sharp dielectric loss peaks are attributed to electronic trap relaxation of zinc interstitial and oxygen vacancy, respectively. [11,12] At the high frequency limit for the relaxation conductivity, namely for the case that ωτ tends to be infinite, another equation can be obtained from Eq. ( 1) as…”

Dielectric spectroscopy studies of ZnO single crystal

“…[1] The existence of vacancy oxygen has been revealed by photoluminescence (PL) spectroscopy and other experiments. [1,[4][5][6][7][8][9] Since the trap energy level E T in the forbidden band is almost fixed for a certain material, the activation energy (E C -E T ) for trapped electron relaxation is almost invariant. [1,10] Therefore, it can be deduced reasonably that the loss peak in ZnO single crystal originates from oxygen vacancies.…”