Ferromagnetic behaviour of ZnO: the role of grain boundaries
نویسندگان
چکیده
The possibility to attain ferromagnetic properties in transparent semiconductor oxides such as ZnO is very promising for future spintronic applications. We demonstrate in this review that ferromagnetism is not an intrinsic property of the ZnO crystalline lattice but is that of ZnO/ZnO grain boundaries. If a ZnO polycrystal contains enough grain boundaries, it can transform into the ferromagnetic state even without doping with "magnetic atoms" such as Mn, Co, Fe or Ni. However, such doping facilitates the appearance of ferromagnetism in ZnO. It increases the saturation magnetisation and decreases the critical amount of grain boundaries needed for FM. A drastic increase of the total solubility of dopants in ZnO with decreasing grain size has been also observed. It is explained by the multilayer grain boundary segregation.
منابع مشابه
Corrigendum: Interfacial dominated ferromagnetism in nanograined ZnO: a μSR and DFT study
Diamagnetic oxides can, under certain conditions, become ferromagnetic at room temperature and therefore are promising candidates for future material in spintronic devices. Contrary to early predictions, doping ZnO with uniformly distributed magnetic ions is not essential to obtain ferromagnetic samples. Instead, the nanostructure seems to play the key role, as room temperature ferromagnetism w...
متن کاملFerromagnetic behaviour of Fe-doped ZnO nanograined films
The influence of the grain boundary (GB) specific area s GB on the appearance of ferromagnetism in Fe-doped ZnO has been analysed. A review of numerous research contributions from the literature on the origin of the ferromagnetic behaviour of Fe-doped ZnO is given. An empirical correlation has been found that the value of the specific grain boundary area s GB is the main factor controlling such...
متن کاملEngineering electrodeposited ZnO films and their memristive switching performance.
We report the influence of zinc oxide (ZnO) seed layers on the performance of ZnO-based memristive devices fabricated using an electrodeposition approach. The memristive element is based on a sandwich structure using Ag and Pt electrodes. The ZnO seed layer is employed to tune the morphology of the electrodeposited ZnO films in order to increase the grain boundary density as well as construct h...
متن کاملPreparation of Fe Substituted ZnO Nanoparticles and Investigation of Their Magnetic Behaviors
Nano-powders of diluted magnetic semiconductor Zn1-xFexO (0.0≤ x ≤0.1) were prepared via the sol-gel auto-combustion method. Crystal structure and phase identification carried out by X-Ray Diffraction (XRD) analysis. Mean crystallite size of the powders was estimated by Scherrer's formula. As M-H loops of the Fe substituted ZnO showed ferromagnetic behavior. The result...
متن کاملThermal runaway, flash sintering and asymmetrical microstructural development of ZnO and ZnO–Bi2O3 under direct currents
DC flash sintering of both pure and 0.5 mol.% Bi2O3-doped ZnO at a relatively high activating field of 300 V/cm has been investigated. It is demonstrated that even high-purity ZnO single crystals can “flash” at 870 C. In comparison, flash sintering occurs at a substantially lower onset temperature of 550 C in ZnO powder specimens, indicating the important roles of surfaces and/or grain boundari...
متن کامل