Structural and Ferromagnetic Properties of Ho-Doped BiFeO3 Films

2017 ◽  
Vol 727 ◽  
pp. 996-1000 ◽  
Author(s):  
Ning An ◽  
Hai Tao Zhang ◽  
Cheng Zhi Liu ◽  
Cun Bo Fan ◽  
Xue Dong ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Raman Spectroscopy ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Sol Gel ◽  
Wave Number ◽  
Ferromagnetic Property ◽  
Peak Intensity ◽  
Structure Morphology ◽  
Xrd Patterns

In order to improve the structural and ferromagnetic property of BiFeO3, the effects of Ho3+ doping is systematically investigated. Pure BiFeO3 and Ho-doped BiFeO3 thin films are fabricated by sol-gel method, and the phase structure, morphology, crystalline structure, ferromagnetic are characterized by XRD, SEM, Raman spectra and VSM, respectively. The XRD patterns of the samples indicate that all the compounds crystallize in rhombohedral distorted perovskite structure with space group R3c and the Ho substitution can suppress the intrinsic formation of the miscellaneous phase. The SEM proves that along with the increasing of Ho concentration, the surface roughness of BiFeO3 is decreased due to the reduction of defects in the preparation. From the Raman spectroscopy, it is found that the peak intensity of 8 modes in Bi1-xHoxFeO3 are increased and the modes shift to higher wave number. Besides, the VSM results show that the ferromagnetic of the samples is enhanced with increasing of Ho concentration. When x=0.1, Ms is improved to be 4.8emu/g. The results can prove that the Ho3+ doping can reduce the volatilization of Bi3+, decrease the concentration of oxygen vacancies and improve the room-temperature ferromagnetic of BiFeO3.

Synthesis, Characterization and Properties of PANI/(La-Nd Doped BaFe12O19) Composites

2017 ◽  
Vol 727 ◽  
pp. 327-334
Author(s):  
Yan Wang ◽  
Jun Wang ◽  
Xiao Fei Zhang ◽  
Ya Qing Liu
Keyword(s):  
Sol Gel ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Structure Morphology ◽  
Xrd Patterns ◽  
Hexagonal Platelet ◽  
Peak Value ◽  
Properties Of Composites

La-Nd co-doped barium hexaferrites, Ba0.7(LamNdn)0.3Fe12O19 (D-BaM), were successfully prepared by sol-gel method. PANI / D-BaM composites were synthesized by in-situ polymerization in solution. The structure, morphology and properties of samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), four-probe conductivity tester and vector network analyzer. The XRD patterns showed that the crystal structure of all the samples exist as M-type phases. The SEM images revealed that the particles presented a hexagonal platelet-like morphology. The magnetic properties could be improved by substitutions of La and Nd ions. The saturation magnetization (Ms) and coercive force (Hc) increased with the change of La / Nd ratio to the maximum at La / Nd = 3:1. The doped particles have also been embedded in conductive PANI to prepare electromagnetic materials, and the conductivity kept on the order of 10-2. The microwave absorbing properties of composites at 30 MHz-6 GHz improved obviously, the peak value of reflection loss could reach-7.5 dB.

scholarly journals Studies on Structural and Morphological Properties of Multidoped Ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) as Solid Solutions

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Marija Stojmenović ◽  
Maja C. Pagnacco ◽  
Vladimir Dodevski ◽  
Jelena Gulicovski ◽  
Milan Žunić ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Solid Solutions ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Fluorite Structure ◽  
Lattice Parameter ◽  
Morphological Properties ◽  
Fluorite Type ◽  
Potential Improvement

The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) with the fluorite type crystal structure of CeO2were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced into the ceria lattice when Ce4+ions were replaced with cations (dopants) of lower valence state (3+), which may indicate the potential improvement of ionic conductivity. Additionally, the presence of oxygen vacancies in the lattice ceria, as well as very developed grain boundaries, gives a new possibility for potential application of obtained nanopowders in the area of room temperature ferromagnetism as spintronics.

Effect of Annealing Atmosphere on the Morphology of Copper Oxide Thin Films Deposited on TiO2 Substrates Prepared by Sol-Gel Process

2013 ◽  
Vol 594-595 ◽  
pp. 113-117 ◽  
Author(s):  
Dewi Suriyani Che Halin ◽  
Ibrahim Abu Talib ◽  
Abdul Razak Daud ◽  
Muhammad Azmi Abdul Hamid
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Grain Size ◽  
Copper Oxide ◽  
Spin Coating ◽  
Sol Gel ◽  
Annealing Atmosphere ◽  
Oxide Thin Films ◽  
Different Temperatures ◽  
Xrd Patterns

Copper oxide films were prepared via sol-gel like spin coating starting from methanolic solutions of cupric chloride onto the TiO2 substrates. Films were obtained by spin coating under room conditions (temperature, 25-30 °C) and were subsequently annealed at different temperatures (200-400 °C) in oxidizing (air) and inert (N2) atmospheres. X-ray diffraction (XRD) patterns showed crystalline phases, which were observed as a function of the annealing conditions. The film composition resulted single or multi-phasic depending on both temperature and atmosphere. The grain size of film was measured using scanning electron microscopy (SEM) and the surface roughness of thin films was characterized by atomic force microscopy (AFM). The grain size of which was annealed in air at 300 °C was 30.39 nm with the surface roughness of 96.16 nm. The effects of annealing atmosphere on the structure and morphology of copper oxide thin films are reported.

Room-Temperature Ferromagnetism in Co-Doped SrTiO3 Nanofibres

2012 ◽  
Vol 512-515 ◽  
pp. 1438-1441
Author(s):  
Wei Zhang ◽  
He Ping Li ◽  
Wei Pan
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Magnetic Ordering ◽  
Second Phase ◽  
Co Doped

In this article, Co-doped SrTiO3 nanofibres have been prepared by electrospinning from a sol-gel precursor and the following calcination at 923K. XRD results confirmed that no second phase was formed, and Co ions successfully occupied the Ti sites. By annealing in hydrogen, oxygen vacancies and (Co-H-Co) were formed, which both contributed to the magnetic ordering in SrTi1-xCoxO3 nanofibres are at 300K.

scholarly journals Microstructural and Mössbauer Spectroscopy Studies ofMg1-x ZnxFe2O4x=0.5,0.7Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Jinpei Lin ◽  
Yun He ◽  
Qing Lin ◽  
Ruijun Wang ◽  
Henian Chen
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Zinc Concentration ◽  
Magnetic Phase ◽  
Sol Gel ◽  
Paramagnetic Behavior ◽  
Different Temperatures ◽  
Phase Spinel ◽  
Spectroscopy Studies ◽  
Xrd Patterns

Zinc substituted magnesium ferriteMg1-xZnxFe2O4(x=0.5,0.7)powders have been prepared by a sol-gel autocombustion method. XRD patterns show that the specimens withx=0.5and 0.7 exhibit single-phase spinel structure, and more content of Zn in specimens is favorable for the synthesis of pure Mg-Zn ferrites. Room temperature Mössbauer spectra ofMg1-xZnxFe2O4annealed at 800°C display transition from ferrimagnetic behavior to super paramagnetic behavior with increase in zinc concentration. The Mössbauer spectras of Mg0.5Zn0.5Fe2O4annealed at different temperatures display the magnetic phase change of the ferrite particles.

Cr-Doping-Induced Ferromagnetism in CeO2-δ Nanopowders

2014 ◽  
Vol 975 ◽  
pp. 42-49
Author(s):  
Nilson S. Ferreira ◽  
Marcelo Andrade Macedo
Keyword(s):  
Raman Spectroscopy ◽  
Saturation Magnetization ◽  
Calcination Temperature ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Fluorite Structure ◽  
Sol Gel Process ◽  
Cr Doping

The room-temperature ferromagnetism of Cr-doped cerium oxide (Ce0.96Cr0.04O2δ) nanopowders synthesized using a sol-gel process is reported in this paper. XRD and Raman spectroscopy confirm that the Cr atoms successfully displaced some of the Ce atoms in the CeO2lattice without forming any impure phases. The results also confirmed that all calcined samples exhibited a single-phase fluorite structure. The crystallite size (as confirmed by XRD) and the particle size (as confirmed by Raman spectroscopy) increased as the calcination temperature increased. Magnetic measurements indicated that the room-temperature ferromagnetism of the sample was sensitive to the calcination temperature. When the calcination temperature increased, the saturation magnetization decreased while the coercivity increased, which corresponds to less dense and larger particles. The calcined sample at 400°C exhibited superior magnetic properties with the highest saturation magnetization (Ms) of 2.5 × 10-2emu/g (Hc~ 1.27 kOe). The results of the Raman and X-ray photoelectron spectroscopies suggest that the nature of the observed room temperature ferromagnetism in the samples are likely a result of the oxygen vacancies induced by Cr-doping in CeO2.

scholarly journals Synthesis of SrFe12O19 by sol-gel method and its morphology and magnetic properties

2016 ◽  
Vol 19 (3) ◽  
pp. 5-10
Author(s):  
Quynh Anh Bao Le ◽  
Vu Hoang Nguyen ◽  
Hoang Thi Thuy Tran ◽  
Ha Ky Phuong Huynh
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Single Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
Gel Method ◽  
Sol Gel Method ◽  
Structure Morphology ◽  
Xrd Patterns

In this research, strontium hexa-ferrite nanoparticles (SrFe12O19) were synthesized by sol-gel method. The crystal structure, morphology and magnetic properties of nanoparticles were investigated using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirmed the formation of single phase M-type hexagonal crystal structure for powders which was calcined above 700oC. The product shows the magnetization of 66 emu/g, which is consistent with pure hexa-ferrite obtained by other methods, and the magnetic coercivity of 6,145 kOe higher than expected for this hexa-ferrite. The powder morphology is composed of aggregates of hexagonal particles with an average particles size of above 100nm.

Ferromagnetic Property of Co and Fe-Implanted ZnO Thin Film at Room Temperature

2006 ◽  
Vol 52 ◽  
pp. 42-47 ◽  
Author(s):  
W.K. Choi ◽  
B. Angadi ◽  
H.C. Park ◽  
J.H. Lee ◽  
Jong Han Song ◽  
...  
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Zno Thin Films ◽  
High Resistivity ◽  
Zno Thin Film ◽  
Ferromagnetic Property ◽  
Before And After ◽  
Xrd Patterns

The results Co and Fe implanted ZnO thin films were studied before and after 200 MeV Ag ion irradiation. The as-implanted films shows the presence of nano sized Co and Fe clusters as seen through XRD patterns and exhibited high resistivity compared to un-implanted films. After Ag ion irradiation the Co and Fe clusters get dissolved in ZnO lattice and the films resistivity reduced to half of the as implanted values. The magnetic properties of Ag irradiated films were confirmed through magnetization hysteresis and Co implanted films exhibit higher magnetization compared to Fe implanted films.

Synthesis and Properties of Lead Free Ferroelectric Na0.5Bi0.5TiO3 Ceramic at Different Sintering Temperature

2015 ◽  
Vol 830-831 ◽  
pp. 620-623 ◽  
Author(s):  
Kusum Parmar ◽  
Hakikat Sharma ◽  
Sarita Sharma ◽  
N.S. Negi
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Lead Free ◽  
Characteristic Absorption Band ◽  
Different Temperatures ◽  
Xrd Patterns ◽  
Rhombohedral Symmetry

Lead Free Ferroelectric Na0.5Bi0.5TiO3 (NBT) Ceramic has been synthesized using sol gel method. The prepared NBT samples have been sintered at different temperatures 850°C, 950°C, 1050°C and 1150°C to achieve best sintering temperature. Structural analyses have been carried out using XRD and FTIR measurements. XRD patterns confirm perovskite structure having rhombohedral symmetry for all samples which is also supported by characteristic absorption band at ~627cm-1 in FTIR spectra. Dielectric properties of NBT samples with frequency and temperature have been studied. NBT sample sintered at 1050°C exhibit comparatively high value of dielectric constant (ε’) and phase transition temperature (Tm). Ferroelectric properties of NBT samples have been studied at room temperature. Comparatively, better ferroelectric properties are observed for NBT sample having remnant polarization (Pr)~ 14.7 μC/cm2and coercive field (Ec)~ 26.8 kV/cm sintered at 1050°C.

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