Structure and physical properties of hydrogenated (Co + Al)-doped ZnO films: Comparative study with co-doped ZnO films

Samoshkina, Yu.E.; Édelman, I. S.; Chou, Hsiung; Lin, Hsien-Chi; Dwivedi, G. D.; Petrov, Dmitry; Жарков, С. М.; Зеер, Г. М.; Мolokeev, Maxim S.

doi:10.1016/j.mseb.2020.114943

Cited by 6 publications

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“…Taking into account the relatively high content of Co in the studied films ( Table 1 ), one can suppose the nanoparticles described by the shown FC-ZFC curves to consist of metallic Co. Though the X-ray diffraction patterns obtained for the films exhibited diffraction peaks corresponding only to the ZnO crystal [ 23 , 24 ], the element-selective XANES spectroscopy at the Co K-edge confirmed the presence of metallic cobalt in the CZO:20 and CZO:30 films. In combination with XRFA data, the relative content of metallic cobalt in the films was estimated as 7.6% and 13%, respectively [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

“…Magneto-optical MCD spectra of the studied films were measured earlier and presented in [ 24 ]. Note that the MCD effect is observed in transmitted light and characterizes the absorption of the medium.…”

Section: Resultsmentioning

confidence: 99%

“…The inequality GMR CZO:20 > GMR CAZO:20 can be explained by the large number of V Zn defects in the CAZO:20 film. The correlation between the films thickness and the amount of zinc in the samples was traced previously [ 24 ]. The CAZO:20 film is thinner and therefore contains more zinc vacancies.…”

Section: Discussionmentioning

confidence: 99%

“…The study of the morphology and chemical composition of the polycrystalline films (ex situ) showed that the thickness of the samples and Zn/Co ratio in them decrease with an increase in the hydrogen concentration in the sputtering chamber [ 24 ]. The thickness of the ZnCoO:H (CZO:H) and ZnCoAlO:H (CAZO:H) films, as well as the percentage of doping elements in them, calculated from the data of X-ray fluorescence spectrometer S4 Pioneer (Bruker, Karlsruhe, Germany) [ 24 ] are presented in Table 1 . This behavior is explained by a decrease in the Zn amount in the films under the indicated deposition conditions.…”

Section: Methodsmentioning

confidence: 99%

“…These targets were prepared from high purity ZnO (99.999%), Co 3 O 4 (99.9985%), and Al 2 O 3 (99.997%) powders by a standard two-step, solid-state reaction method. The targets synthesis is described in detail in [23,24]. The film's deposition was carried out at a total pressure of 30 mTorr and a forward RF power of 80 W. The substrate temperature was 450 • C. Deposition time was 20 min.…”

Section: Methodsmentioning

confidence: 99%

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Particles–Matrix Bond in ZnCoO:H and ZnCoAlO:H Films: Issues of Magnetism and Spin Injection

et al. 2023

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ZnCoO:H and ZnCoAlO:H films were synthesized by radio frequency magnetron sputtering in a (1 − x)Ar + xH2 mixed atmosphere with x = 0.2–0.5. The films contain different amounts of metallic Co particles (from 7.6% and higher) ~4–7 nm in size. The magnetic and magneto-optical (MO) behavior of the films was analyzed in combination with their structural data. The samples exhibit high values of magnetization (up to 377 emu/cm3) and MO response at room temperature. Two situations are considered: (1) the film magnetism is associated only with isolated metal particles and (2) magnetism is present both in the oxide matrix and in metal inclusions. It has been established that the formation mechanism of the magnetic structure of ZnO:Co2+ is due to the spin-polarized conduction electrons of metal particles and zinc vacancies. It was also found that in the presence of two magnetic components in the films, these components are exchange-coupled. In this case, the exchange coupling generates a high spin polarization of the films. The spin-dependent transport properties of the samples have been studied. A high value of the negative magnetoresistance of the films at room temperature (~4%) was found. This behavior was explained in terms of the giant magnetoresistance model. Thus, the ZnCoO:H and ZnCoAlO:H films with high spin polarization can be considered as sources of spin injection.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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