scholarly journals Comparative Study on AC Susceptibility of YBa2Cu3O7−δ Added with BaZrO3 Nanoparticles Prepared via Solid-State and Co-Precipitation Method

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 655 ◽  
Author(s):  
Nurhidayah Mohd Hapipi ◽  
Jee Lim ◽  
Soo Chen ◽  
Oon Lee ◽  
Abdul Shaari ◽  
...  
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Grain Boundaries ◽  
Ac Susceptibility ◽  
Precipitation Method ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Weight Percentage ◽  
Average Grain Size ◽  
Co Precipitation

Polycrystalline samples of YBa2Cu3O7−δ (Y-123) added with x mol% of BaZrO3 (BZO) nanoparticles (x = 0.0, 2.0, 5.0, and 7.0) were synthesized using co-precipitation (COP) and solid-state (SS) method. X-ray diffraction (XRD) patterns showed the formation of Y-123 and Y-211 as the major and minor phases, respectively. The samples prepared using COP method showed higher weight percentage of Y-123 phase (≤98%) compared to the SS samples (≤93%). A peak corresponding to BZO was also found in the samples added with BZO nanoparticles. The increasing intensity of the BZO peak as the BZO amount increased showed the increasing amount of the unreacted nanoparticles in the samples. Refinement of unit cell lattice parameters indicated that all the samples have an orthorhombic crystal structure and there is no orthorhombic-tetragonal phase transformation. As observed using scanning electron microscopy (SEM), all the samples showed randomly distributed grains with irregular shape. The average grain size for the pure sample prepared using COP method is smaller (0.30 µm) compared with that of the pure SS sample (1.24 µm). Addition of 7.0 mol% BZO led to an increase of average grain size to 0.50 μm and 2.71 μm for the COP and SS samples, respectively, indicating grain growth. AC susceptibility (ACS) measurement showed a decrease in the onset critical temperature, Tc-onset with BZO addition. Comparatively, Tc-onset for the COP samples is higher than that of the SS samples. The value of Josephson’s current, Io increased up to 2.0 mol% BZO addition, above which the Io decreased more drastically for the SS samples. The value of Io is 53.95 μA and 32.08 μA for the 2.0 mol% BZO added SS and COP samples, respectively. The decrease of Io is attributed to the distribution of BZO particles at the grain boundaries as also reflected in the drastic decrease of phase lock-in temperature, Tcj. As a result of smaller average grain size, the presence of more grain boundaries containing insulating BZO particles led to lower Io in the COP samples.

Comparison between Solid State Reaction and Coprecipitation Method of Titanium Oxide Addition on the YBa2Cu3Oδ Ceramics

2020 ◽  
Vol 1010 ◽  
pp. 187-193
Author(s):  
Ali Arlina ◽  
Nadiah Ameram ◽  
Nik Alnur Auli
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Sem Images ◽  
Orthorhombic Crystal Structure ◽  
Oxide Addition ◽  
Co Precipitation

In this work, comparison of TiO2 additions on the physical properties of YBa2Cu3Oδ superconductor system with nominal starting compositions at x= 0, 1, 2, and 5 wt.% was studied derived via solid state reaction and co-precipitation method. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result from XRD shown that all the samples were polycrystalline for solid state reaction, while single phase appear for co-precipitation methods. The intensity of the peak become higher with increasing amount of TiO2 addition indicating the presence of increased amount of the unreacted in the samples. The refine lattice parameters indicated that all the samples have an orthorhombic crystal structure without occurrence of orthorhombic-tetragonal phase transformation. Furthermore, from SEM images for solid state reaction and co-precipitation method showed that the grain size of the samples decreased with TiO2 increased. Small addition of TiO2 derived from co-precipitation method enhanced the YBCO microstructures.

scholarly journals Fabrication of highly-transparent Er:CaF2 ceramics by hot-pressing technique

2014 ◽  
Vol 32 (3) ◽  
pp. 358-363 ◽  
Author(s):  
W. Zhou ◽  
F. Cai ◽  
G. Zhi ◽  
B. Mei
Keyword(s):  
Grain Size ◽  
Optical Transmittance ◽  
Uniaxial Pressure ◽  
Precipitation Method ◽  
Potential Candidate ◽  
Erbium Ions ◽  
Sintering Additive ◽  
Average Grain Size ◽  
Mean Grain Size ◽  
Co Precipitation

AbstractHighly-transparent trivalent erbium ion doped calcium fluoride (5 mol % Er:CaF2) ceramics were fabricated by a hotpressing (HP) method using high-purity Er:CaF2 nanoparticles, which were synthesized by co-precipitation method. The mean grain size of the nanoparticles was about 24.7 nm. The nanoparticles were sintered at 600 °C, 700 °C, 800 °C and 900 °C, respectively, for 30 min under a uniaxial pressure of 30 MPa and vacuum of 10−3 Pa with 1 mol % lithium fluoride (LiF) as sintering additive. The 5 mol % Er:CaF2 ceramics sintered at 800 °C exhibits high density and pore-free microstructure with an average grain size of about 8 μm. The optical transmittance of the transparent ceramics is close to 85 % at visible and nearinfrared wavelengths. The strong and broad absorptions peaks corresponding to characteristic absorption of trivalent erbium ions make the ceramics a potential candidate for infrared and upconversion laser operating.

STRUCTURAL AND OPTICAL PROPERTIES OF Eu3+ DOPED CERIUM OXIDE NANOPHOSPHORS

2011 ◽  
Vol 04 (01) ◽  
pp. 13-16 ◽  
Author(s):  
R. SRINIVASAN ◽  
A. CHANDRA BOSE
Keyword(s):  
Grain Size ◽  
Diffuse Reflectance Spectroscopy ◽  
Site Occupancy ◽  
Precipitation Method ◽  
Ceria Nanoparticles ◽  
Doped Ceria ◽  
Red Color ◽  
Average Grain Size ◽  
Co Precipitation ◽  
The Eu

Europium (3%) doped ceria nanoparticles were successfully prepared by 72 h hydrolysis assisted co-precipitation method. The average grain size of the as-prepared sample was 11 nm. The grain sizes were 12 and 18 nm for samples annealed at 500°C and 800°C respectively. The grain size effect on optical bandgap is investigated from diffuse reflectance spectroscopy (DRS). The orange and red color emissions of europium doped ceria nanoparticles were investigated by photoluminescence (PL) spectra under excitation of 330 nm. The high intense orange emission peak was found at 591 nm for as-prepared and annealed nanoparticles. This is the characteristic peak of the Eu 3+ ion corresponding to the parity allowed magnetic dipole transition between the 5 D 0–7 F 1 states. Site occupancy of europium ions was estimated by Red (R)/Orange (O) intensity ratio using PL spectrum.

Modification in structural, functional, thermal, dielectric, impedance and nonlinear optical properties of ammonium pentaborate crystal by addition of di-sodium sulphide nanoparticles

2019 ◽  
Vol 33 (07) ◽  
pp. 1950084
Author(s):  
A. P. Kochuparampil ◽  
J. H. Joshi ◽  
H. O. Jethva ◽  
M. J. Joshi
Keyword(s):  
Nonlinear Optical ◽  
Complex Impedance ◽  
Precipitation Method ◽  
Dielectric Study ◽  
Sodium Sulphide ◽  
Frequency Range ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Nlo Properties ◽  
Co Precipitation

Ammonium penataborate (APB) crystals are well known for their nonlinear optical (NLO) properties. Attempt is made to study the changes produced by addition of chalcogenide compound sodium sulphide in APB crystals. Di-sodium sulphide (Na2S) is soluble in water and its solubility is further increased for Na2S nanoparticles. The Na2S nanoparticles are synthesized by using co-precipitation method followed by microwave irradiation. The slow solvent evaporation method is used to grow pure and Na2S added APB crystals. Pure and Na2S added APB crystals possess orthorhombic crystal structure with the mixed phase nature for the Na2S added APB. The presence of sodium in APB is confirmed by AAS study. In FTIR spectra the absorption peak of S–H asymmetric stretching is observed for Na2S added APB indicating the presence of sulphur. The thermal stability of APB crystal is enhanced on doping the Na2S in it. The dielectric study is also carried out within this frequency range. The Jonscher’s power law is applied to AC conductivity data. The impedance spectroscopy study is carried out at room temperature within 100 Hz to 1 MHz frequency range. The complex impedance and modulus plots are drawn. The complex impedance plots indicate only the grain contribution. The Kurtz and Perry powder study indicates that all the crystals are exhibiting NLO properties with varying SHG efficiency.

Preparation and Microstructure of Co-Ferrite Fine Powder

2011 ◽  
Vol 328-330 ◽  
pp. 1365-1368
Author(s):  
Chang Sen Zhang ◽  
Lei Yang ◽  
Feng Zhou
Keyword(s):  
Grain Size ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Fine Powder ◽  
Precipitation Method ◽  
Mechanical Grinding ◽  
Gel Method ◽  
Sol Gel Method ◽  
Average Grain Size ◽  
Co Precipitation

Cobalt ferrites were prepared by citrate sol-gel method, chemical co-precipitation, mechanical grinding, respectively. The grain size, morphology, and the size of crystal particles were studied by x-ray diffraction (XRD) and scanning electron microscope (SEM). Cobalt ferrite showed different morphologys when prepared by different methods, It was tapered corners which prepared by sol-gel method; It was tetrahedral which prepared by mechanical grinding method; It was sphere which prepared by chemical co-precipitation method. The average grain size of cobalt ferrite was less than 100nm, while particles prepared by chemical precipitation method were the smallest. The size of Cobalt ferrite prepared by sol-gel method was decreased with the cobalt content increased.

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

scholarly journals Effect of Sintering Temperature on the Microstructure, Electrical and Magnetotransport Properties of La0.67Sr0.33MnO3 Compound

2014 ◽  
Vol 895 ◽  
pp. 319-322
Author(s):  
Lim Kean Pah ◽  
Abdul Halim Shaari ◽  
Chen Soo Kien ◽  
Chin Hui Wei ◽  
Albert Gan ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
Sintering Temperature ◽  
Measurement Range ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Metal Insulator ◽  
Higher Temperature ◽  
Co Precipitation ◽  
Grain Surface

In this work, we report the effect of sintering temperature (900°C, 1000°C, 1100°C and 1200°C) on the electrical and magnetotransport properties of polycrystalline La0.67Sr0.33MnO3 (LSMO). Single phase of LSMO hexagonal structure (R-3c) accompanied with minor phases was successfully synthesized by co-precipitation method. With increasing sintering temperature, grain growth was promoted and grain connectivity was improved. It was found that an enhancement of resistivity on smaller grain size was due to larger grain surface over volume (grain boundaries effect). The shifting of the metal-insulator transition (TMI) to higher temperature was also responsible for observed changes in physical properties. TMI of 900°C, 1000°C and 1100°C were 232 K, 278 K and 298 K respectively however 1200°C was out of measurement range (higher than 300 K). In summary, CP900 with smaller grain size distribution (~200 nm) displayed the highest resistivity and MR% of -19.2% (at 80 K, 10 kG).

The preparation of organoboron-based stilbene nanoparticles for cell imaging

2016 ◽  
Vol 4 (33) ◽  
pp. 5515-5518 ◽  
Author(s):  
Huanxiang Yuan ◽  
Lifang Wang ◽  
Shuhong Li ◽  
Haiyan Liang ◽  
Chichong Lu ◽  
...  
Keyword(s):  
Solid State ◽  
Cell Imaging ◽  
Precipitation Method ◽  
Co Precipitation

In this work, a series of nanoparticles were prepared assembled by a highly emissive solid-state organoboron-based stilbene (OBS) and PS-PEG-COOH via regulating the ratio of these two compounds using a co-precipitation method.

Effect of Sintering on Structural and Transport Properties on Nanosized Pr0.85Na0.15MnO3

2015 ◽  
Vol 1107 ◽  
pp. 272-277 ◽  
Author(s):  
Siau Wei Ng ◽  
Kean Pah Lim ◽  
S.A. Halim ◽  
Hassan Jumiah ◽  
Albert H.M. Gan ◽  
...  
Keyword(s):  
Grain Size ◽  
Transport Properties ◽  
Electrical Transport ◽  
Boundary Effect ◽  
Sol Gel ◽  
Magnetic Layer ◽  
Electrical Transport Properties ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Semiconductor Behavior

We have investigated the structural, microstructure and electrical transport properties of nanosized Pr0.85Na0.15MnO3 (PNMO) synthesized by sol-gel technique and sinter from 600°C to 1000°C. The grain size increases from 67 nm (S600) up to 284 nm (S1000) due to the grain growth during heat treatment. XRD showed that single phase orthorhombic crystal structure of PNMO is fully forms started at 600°C. The resistivity decreased with the increased of grain size and crystallite size due to the reduction of grain boundary effect (dead magnetic layer) which improved their grain conductivity.All samples showed semiconductor behavior where their metal insulator transition temperatures (TMIT) were estimated to be lower than 80K.

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