Observation of room temperature ferromagnetic behavior in cluster-free, Co doped HfO2 films

2007 ◽  
Vol 91 (8) ◽  
pp. 082504 ◽  
Author(s):  
Y. H. Chang ◽  
Y. L. Soo ◽  
W. C. Lee ◽  
M. L. Huang ◽  
Y. J. Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ferromagnetic Behavior ◽  
Co Doped

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.

scholarly journals Synthesis of Cu and Ce co-doped ZnO nanoparticles: crystallographic, optical, molecular, morphological and magnetic studies

2017 ◽  
Vol 35 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Mohit Rawat ◽  
Jasmeet Singh ◽  
Jagpreet Singh ◽  
Chamkaur Singh ◽  
Amritpal Singh ◽  
...  
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Research Work ◽  
Yellow Emission ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Ferromagnetic Behavior ◽  
Magnetic Studies ◽  
Transmission Electron Microscopy Analysis ◽  
Co Doped

Abstract In the present research work, crystallographic, optical, molecular, morphological and magnetic properties of Zn1-xCuxO (ZnCu) and Zn1-x-yCeyCuxO (ZnCeCu) nanoparticles have been investigated. Polyvinyl alcohol (PVA) coated ZnCu and ZnCeCu nanoparticles have been synthesized by chemical sol-gel method and thoroughly studied using various characterization techniques. X-ray diffraction pattern indicates the wurtzite structure of the synthesized ZnCu and ZnCeCu particles. Transmission electron microscopy analysis shows that the synthesized ZnCu and ZnCeCu particles are of spherical shape, having average sizes of 27 nm and 23 nm, respectively. The incorporation of Cu and Ce in the ZnO lattice has been confirmed through Fourier transform infrared spectroscopy. Room temperature photoluminescence spectra of the ZnO doped with Cu and co-doped Ce display two emission bands, predominant ultra-violet near-band edge emission at 409.9 nm (3 eV) and a weak green-yellow emission at 432.65 nm (2.27 eV). Room temperature magnetic study confirms the diamagnetic behavior of ZnCu and ferromagnetic behavior of ZnCeCu.

Semiconducting and ferromagnetic behavior of sputtered Co-doped TiO[sub 2] thin films above room temperature

2002 ◽  
Vol 91 (10) ◽  
pp. 8093 ◽  
Author(s):  
Wan Kyu Park ◽  
Ricardo J. Ortega-Hertogs ◽  
Jagadeesh S. Moodera ◽  
Alex Punnoose ◽  
M. S. Seehra
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Ferromagnetic Behavior ◽  
Co Doped

Magneto-Opto Electronic Applications of Conductive and Room Temperature Ferromagnetic (Al, Mn) Co-Doped ZnO Particles with Visible Emission

2020 ◽  
Vol 20 (6) ◽  
pp. 3913-3918 ◽  
Author(s):  
Divya Rehani ◽  
Swati Bishnoi ◽  
Manish Saxena ◽  
Shailesh Narain Sharma
Keyword(s):  
Room Temperature ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
Hexagonal Wurtzite Structure ◽  
Solid State Reaction Method ◽  
Ferromagnetic Behavior ◽  
Maximum Conductivity ◽  
Doped Zno ◽  
Mn Doped ◽  
Co Doped

The Mn, Al co-doped ZnO samples were synthesized using solid-state reaction method and were annealed in furnace at 300 °C, 600 °C and 900°C temperature. All the samples prepared were investigated in detail for analysis of their structural, morphological, optical, magnetic and electrical behavior. The XRD data confirmed the hexagonal wurtzite structure of pristine, Mn doped and Al, Mn co-doped ZnO. For morphological investigation SEM and TEM techniques were employed. The PL properties of the ZnO:Mn, Al sample revealed emission in the blue region (415–438 nm). Furthermore, IV studies were carried out to examine the conductivity of the ZnO:Mn, Al samples and maximum conductivity was found in the sample with 5% Al doping and annealing temperature 600 °C. The magnetic measurements revealed room temperature ferromagnetic behavior in the optimized ZnO:Mn, Al sample annealed at 600 °C which indicates its suitability for Magneto-Opto Electronic Applications.

SYNTHESIS AND ROOM TEMPERATURE FERROMAGNETIC PROPERTY OF COBALT DOPED ZINC OXIDE

2009 ◽  
Vol 23 (14) ◽  
pp. 1799-1804 ◽  
Author(s):  
FENGYU WEN
Keyword(s):  
Room Temperature ◽  
Combustion Process ◽  
Combustion Method ◽  
Magnetization Measurement ◽  
Ferromagnetic Behavior ◽  
Vibrating Sample Magnetometer ◽  
Ferromagnetic Property ◽  
X Ray ◽  
Microwave Assisted ◽  
Co Doped

Nanocrystalline Co -doped ZnO ( Zn 1-x Co x O , x = 0.00, 0.05) powders have been successfully prepared by a microwave-assisted combustion method using Zn ( NO 3)2·6 H 2 O and Co ( NO 3)2·6 H 2 O as starting materials and urea as fuel. The as-prepared products were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). It was found that the combustion process took only a few minutes to obtain Zn 1-x Co x O powders. The field dependence of magnetization measurement at room temperature for the as-prepared Zn 0.95 Co 0.05 O powders exhibited the obvious ferromagnetic behavior.

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.

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.

Room temperature ferromagnetic behavior in cluster free, Co doped Y2O3 dilute magnetic oxide films

2012 ◽  
Vol 101 (16) ◽  
pp. 162403 ◽  
Author(s):  
C. N. Wu ◽  
S. Y. Huang ◽  
W. C. Lee ◽  
Y. H. Chang ◽  
T. S. Wu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Oxide Films ◽  
Ferromagnetic Behavior ◽  
Magnetic Oxide ◽  
Dilute Magnetic Oxide ◽  
Co Doped
Sign in / Sign up

Export Citation Format

Share Document