The composition analysis was performed using an energy-dispersive X-ray spectrometer (EDS) attached to the TEM. Thin slices for cross-sectional TEM analysis were prepared using a dual-beam focused-ion-beam (FIB) instrument. The areas selected for cutting selleck compound with an ion beam were protected by an amorphous carbon overlayer. Adjust the beam currents to mill initial trenches, thin the central membrane, and polish for check details electron transparency of membrane. Finally,
FIB milling was used to capture a free membrane from trenches for a TEM analysis. The room temperature-dependent photoluminescence (PL) spectra were captured using the 325-nm line of a He-Cd laser. A superconducting quantum-interference device magnetometer Selleck CA4P was used to measure the magnetic properties of the samples. Results and discussion Figure 1 displays the X-ray diffraction (XRD) patterns of the ZFO thin films grown on various substrates. The XRD patterns show several sharp and intense Bragg reflections originating from the ZFO structure (according to JCPDS No. 89–1012), confirming that the ZFO thin films exhibited excellent crystalline quality. The absence of ZnO and Fe x O y phases in the XRD patterns indicated that an exceptional ZFO compound was formed. The ZFO films grown on the YSZ and STO substrates exhibited highly (222) and (400) crystallographic
orientations, respectively. By contrast, the film grown on the Si substrate was randomly oriented. Most of the grains on the ZFO thin film grown on the Si substrate were (311)-oriented and some were (220)-oriented. The lattice constants CYTH4 of the ZFO thin films were derived from the observed Bragg reflections and were independent of the substrate types used in this study. The lattice constants of the ZFO thin films were approximately 0.843 nm, and this value was similar to that of its bulk counterpart (approximately 0.844 nm) [16], indicating that the highly oriented ZFO thin films were not affected by lattice distortion of the substrates (caused by a lattice mismatch between film and substrate). This might be attributed to the film thickness
(approximately 125 nm), which markedly exceeded the critical value for misfit strain relaxation [17, 18]. Figure 1 XRD patterns of the ZFO thin films on various substrates: (a) YSZ (111), (b) SrTiO 3 (100), and (c) Si (100). The atomic percentage of the Fe/Zn and binding states of the Zn and Fe constituent elements for the as-deposited ZFO thin film was evaluated based on the narrow-scan XPS spectra of Zn and Fe. The Fe/Zn atomic ratio was approximately 2.04, and this ratio is similar to the Fe/Zn stoichiometric composition of the ZFO. Figure 2a shows a Zn2p narrow-scan XPS spectrum. The binding energies of Zn2p3/2 and Zn2p1/2 were 1,020.7 and 1,043.7 eV, respectively. These binding energies are close to the reported values of the binding state of Zn2+[19].