ROOM-TEMPERATURE FERROMAGNETIC PROPERTIES OF Co-DOPED ZnO NAOROD ARRAYS

2013 ◽  
Vol 27 (15) ◽  
pp. 1362010 ◽  
Author(s):  
C. L. ZHANG ◽  
C. G. HU
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Polarized Electrons ◽  
Spin Polarized ◽  
Doped Zno ◽  
Zinc Foils ◽  
Co Doped

Co -doped ZnO rod arrays were fabricated on zinc foils by a hydrothermal method. X-ray diffraction results indicate that the samples have wurtzite crystalline structure without metallic Co or other secondary phases detected. The nanorod arrays exhibit room-temperature ferromagnetic behavior for different Co concentration. The influence of Co on the magnetic properties of ZnO was studied by the first-principles calculations. The exchange interaction between local spin-polarized electrons and conductive electrons is proposed as a cause of the room-temperature ferromagnetism.

Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

2020 ◽  
Vol 16 (4) ◽  
pp. 655-666
Author(s):  
Mona Rekaby
Keyword(s):  
Magnetic Properties ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Structural Defects ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Antiferromagnetic Ordering ◽  
Doped Zno ◽  
Co Doped

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

Hydrothermal Synthesis and Room Temperature Ferromagnetism of Ni-Doped Rod-Like ZnO Particles

2014 ◽  
Vol 934 ◽  
pp. 71-74
Author(s):  
Lian Mao Hang ◽  
Zhao Ji Zhang ◽  
Zhi Yong Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Hexagonal Wurtzite Structure ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Particles

Ni-doped rod-like ZnO particles with doping concentration of 1 at.% were synthesized at 200°C by hydrothermal method and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and superconducting quantum interference device (SQUID). The results show that the as-synthesized samples are pure hexagonal wurtzite structure without metallic Ni or other secondary phases and display rod-like shape with smooth surface. The magnetization measurements reveal that the Ni-doped rod-like ZnO particles show ferromagnetic behavior at room temperature. The saturation magnetization and coercive field are 0.0046 emu/g and 15 Oe, respectively.

Spin-Polarized Room Temperature Ferromagnetism in Co-doped ZnO synthesized by Electrodeposition

2021 ◽  
Author(s):  
Santosh Kumar ◽  
Deepika ◽  
Raju Kumar ◽  
Ritesh Kumar ◽  
Pratyush Vaibhav ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Spin Polarized ◽  
Doped Zno ◽  
Co Doped

Hydrothermal Synthesis, Photoluminescence and Room Temperature Ferromagnetism of Co-Doped Rod-Like ZnO Particles

2014 ◽  
Vol 633-634 ◽  
pp. 292-295
Author(s):  
Lian Mao Hang ◽  
Zhi Yong Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Blue Emission ◽  
Diffraction Field ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Violet Emission ◽  
Zno Particles ◽  
Co Doped

Co-doped rod-like ZnO particles with nominal Co doping concentration of 1 at% were synthesized by hydrothermal method and characterized by X-ray diffraction, field-emission scanning electron microscopy, photoluminescence and superconducting quantum interference device. The results show that the as-synthesized samples are pure hexagonal wurtzite structure without metallic Co or other secondary phases and display rod-like shape with smooth surface. The room temperature PL spectrum of the Co-doped rod-like ZnO particles exhibits a strong blue emission at 440 nm, a shoulder violet emission at 410 nm and a weak green emission centered at 550 nm. The magnetization measurements reveal that the Co-doped rod-like ZnO particles show ferromagnetic behavior at room temperature. The saturation magnetization and coercive field are 0.0125 emu/g and 45 Oe, respectively.

The Room Temperature Ferromagnetism of (N, Co) Co-Doped ZnO Nanopaticles

2014 ◽  
Vol 577 ◽  
pp. 19-22
Author(s):  
Ping Cao ◽  
Yue Bai ◽  
Zhi Qu
Keyword(s):  
Zno Nanoparticles ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Crystal Lattices ◽  
Grown Sample ◽  
N Doping ◽  
Doped Zno ◽  
Zno Crystal ◽  
Zno Nanopaticles ◽  
Co Doped

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.

scholarly journals Doping effect and oxygen defects boost room temperature ferromagnetism of Co-doped ZnO nanoparticles: experimental and theoretical studies

RSC Advances ◽  
2019 ◽  
Vol 9 (40) ◽  
pp. 23012-23020 ◽  
Author(s):  
Yan Zong ◽  
Yong Sun ◽  
Shiyan Meng ◽  
Yajing Wang ◽  
Hongna Xing ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Decomposition Method ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Theoretical Studies ◽  
Thermal Decomposition Method ◽  
Oxygen Defects ◽  
Doped Zno ◽  
Experimental And Theoretical Studies ◽  
Co Doped

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

Structural and Magnetic Properties of Cobalt and Aluminum Co-Doped ZnO Powders

2008 ◽  
Vol 47-50 ◽  
pp. 600-603
Author(s):  
Yan Yan Wei ◽  
Deng Lu Hou ◽  
Rui Bin Zhao ◽  
Zhen Zhen Zhou ◽  
Cong Mian Zhen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Ferromagnetic Behavior ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Al Content ◽  
Infrared Reflection ◽  
Zno Powders ◽  
Ft Ir

A series of Zn0.95-xCo0.05AlxO (x=0, 0.01, 0.02, 0.05, 0.08, 0.10) powders with different percentages of aluminum was fabricated using the sol-gel method. X-ray diffraction (XRD) revealed that the Co ions and Al ions substitute for Zn2+ ions without changing the wurtzite structure. No impurity phases were found. No clusters or precipitates of cobalt or aluminum were found using scanning electron microscope analysis. Fourier transform-infrared reflection (FT-IR) spectrometry was used to examine the infrared transmission properties and revealed that Co ions were incorporated into the lattice as Co2+ substituting for Zn2+. Ferromagnetic behavior in the samples was obtained at room temperature. As the Al content x increased, the room temperature ferromagnetism of the samples was reduced, and when x increased to 0.08, the room temperature ferromagnetism disappeared.

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