(d) Low-magnification TEM image of the ZFO film on the STO. (e) The selected area electron diffraction pattern from the ZFO film and STO was also presented. (f) HRTEM image taken from the ZFO film-STO interfacial region. (g) Low-magnification TEM image of the ZFO film on the Si. (h) The selected area electron diffraction pattern from the ZFO film and Si. (i) HRTEM images and corresponding FFT patterns taken from the ZFO film grown on the Si. Figure 5 shows the room-temperature photoluminescence spectra of the ZFO thin films grown on the various
substrates. A broad peak in the visible emission range and a maximum of approximately 560 to 580 nm were observed for the ZFO thin films. A blue emission band at approximately 468 nm was observed in the Zn-Fe-O compound that had interstitial zinc defects Selleck LCL161 [23]. In the XPS analysis, a symmetrical Zn2p spectrum revealed that there were no excess Zn interstitials Defactinib chemical structure in the ZFO lattices, and hence, no such blue emission band was observed in this study. A similar broad visible band, which was attributed to deep-level emissions caused by surface-oxygen-related
defects, has been widely reported in ZnO oxides [24]. Insufficient oxygen in the sputtering process JQEZ5 order generates oxygen vacancies in the ZFO oxide during crystal growth, and this might have caused surface defects in the film, further inducing a yellow emission band. Figure 5 PL spectra of the ZFO thin films grown on various substrates: (a) YSZ (111), (b) SrTiO 3 (100), and (c) Si (100). Figure 6a,b,c shows the relationship between temperature (T) and magnetization (M) (zero-field-cooled (ZFC) and field-cooled (FC)) for the ZFO thin films.
The M-T curves were similar among the samples. The observed increase in the M of all samples Mannose-binding protein-associated serine protease as the temperature decreased was caused by stronger A-B interaction at lower temperatures in Zn-Fe-O lattices [25]. A non-zero M value was observed up to the maximum measurement temperature (350 K) in this study. The ZFC and FC curves showed great differences in the samples below 40 K. The ZFC curves showed a broad peak with a clear summit region. This proved that the films were in a cluster glass state [26]. The spin-glass transition temperature was observed to be nearly 40 K in this study, which is in agreement with results reported in the literature [27]. The bulk ZFO had a spin-glass transition temperature (T g) of 20 to 30 K. The ZFO thin film had a slightly higher T g value than did the bulk ZFO. This was attributed to the disordered cation distribution of Zn2+ and Fe3+ ions in the spinel structure [10]. Moreover, the random configuration of zinc and iron ions of the spinel structure was associated with oxygen vacancies in the lattices [9]. The XPS analysis results showed that the sputtering-deposited ZFO thin films herein had some degree of oxygen vacancy, which might have contributed to the observed M-T results.