Oxygen vacancies induced room temperature ferromagnetism and enhanced dielectric properties in Co and Mn co-doped ZnO nanoparticles

Author(s):  
Zulfiqar ◽  
Muhammad Zubair ◽  
Aurangzeb Khan ◽  
Tang Hua ◽  
Nasir Ilyas ◽  
...  
2014 ◽  
Vol 577 ◽  
pp. 19-22
Author(s):  
Ping Cao ◽  
Yue Bai ◽  
Zhi Qu

Co-doped ZnO nanoparticles were fabricated by an electrodeposition method. The XPS results show Co ions have doped into the ZnO crystal lattices successfully. The as-grown sample has no ferromagnetism at room temperature. But after an ammine plasma treatment the room temperature ferromagnetism were detected on Co0.04Zn0.96O nanoparticles. The Hall measurement reveals after the treatment the resistivity increase by three orders of magnitude. Although the aspect conductivity is n type, some holes generated by N doping play an important role to induce the ferromagnetic properties for Co doped ZnO sample.


RSC Advances ◽  
2019 ◽  
Vol 9 (40) ◽  
pp. 23012-23020 ◽  
Author(s):  
Yan Zong ◽  
Yong Sun ◽  
Shiyan Meng ◽  
Yajing Wang ◽  
Hongna Xing ◽  
...  

Co-doped ZnO nanoparticles with different dosage concentrations were fabricated by a thermal decomposition method.


2011 ◽  
Vol 10 (01n02) ◽  
pp. 307-311 ◽  
Author(s):  
BAPPADITYA PAL ◽  
P. K. GIRI

We report on the occurrence of room temperature ferromagnetism in Co -doped ZnO nanoparticles (NPs). Doping is performed by ball milling of 3 wt% of Co mixed with ZnO nanopowders (commercial) for durations of 2–8 h. X-ray diffraction data and high-resolution transmission electron microscopy (HRTEM) confirm the absence of metallic Co clusters or any other phase different from würtzite-type ZnO . The magnetization (M–H curve) measured at room temperature exhibits the clear ferromagnetic characteristic with saturation magnetization (Ms) and coercive field (Hc) of the order of 3–4 emu/g and 225 Oe, respectively. Post-growth annealing at 250°C results in an increase of Ms by a small magnitude, while annealing at 500°C results in reduction of Ms. UV–visible absorption spectra show small redshift in the absorption peaks in the Co -doped ZnO NPs due to the incorporation of Co atoms in ZnO lattice. Room temperature photoluminescence studies show enhanced near-band-edge emission at 378 nm in the doped NPs as compared to the undoped NPs indicating low density of defects in the doped ZnO crystals. Contribution of intrinsic defects and magnetic impurities in the observed ferromagnetism is discussed.


2014 ◽  
Vol 195 ◽  
pp. 179-184 ◽  
Author(s):  
Srinatha N ◽  
Basavaraj Angadi ◽  
K.G.M. Nair ◽  
Nishad G. Deshpande ◽  
Y.C. Shao ◽  
...  

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