Synthesis of Polycrystalline LaYO3 with Different Sintering Temperature

2015 ◽  
Vol 819 ◽  
pp. 117-122 ◽  
Author(s):  
N.A. Shafiqa ◽  
M.S. Idris ◽  
C.A. Salmie Suhana ◽  
R.A.M. Osman ◽  
T.Q. Tan

Synthesis of LaYO3 was carried out via conventional solid state reaction method. The polycrystalline samples were sintered at temperatures in the range of 1300 °C to 1500 °C with each deviation is 50 °C. X-ray diffraction (XRD) analysis indicated that the perovskite ceramic obtained its single phase at 1500 °C with ordered monoclinic perovskite structure. The pure phase sample showed 98.79 % relative density and scanning electron micrographs also proved that the porosity of the sample reduced when sample undergo sintering.

2021 ◽  
Vol 317 ◽  
pp. 35-45
Author(s):  
Aaliyawani Ezzerin Sinin ◽  
Walter Charles Primus ◽  
Zainal Abidin Talib ◽  
Chen Soo Kien ◽  
Abdul Halim Shaari ◽  
...  

Composite La0.88Bi0.12Mn0.80Ni0.20O3 was synthesized using the conventional solid-state reaction method with sintering temperature of 1200 °C for 12 hours and the dielectric properties investigated. The X-ray diffraction result shows that the composite has a rhombohedral structure with lattice parameter of a = b = c = 5.5136 Ǻ. Scanning electron microscope shows grains with approximately from 0.8 to 5.4 μm in size with presence of voids. The dielectric permittivity, εʹ and dielectric loss, εʺ were measured in the range of 298 K to 473 K where both are temperature and frequency dependent. At 1 kHz to 100 kHz, the εʹ is around 10000 and the dielectric loss tangent, tan δ is below 1.5. The electric behavior of this composite is best represented by Quasi-dc model which consists of two universal capacitors in parallel. Parameters value from the fitting indicated that high correlations of electrons between inter and intra-clusters. The activation energy, Ea calculated from the conductivity of the sample gives a value of 0.116 eV. Vibrating sample magnetometer shows that the La0.88Bi0.12Mn0.80Ni0.20O3 has a magnetic coercivity, Hc of 36.109 G and retentivity, Br, valued 2.7504 x 10-3 emu/g.


2014 ◽  
Vol 602-603 ◽  
pp. 813-816
Author(s):  
Jian Qiang Zhou ◽  
Ke Pi Chen

The effects of CuO-B2O3(CBO) additive on densification, microstructure, and electrical properties of (Ba0.98Ca0.02)(Sn0.04Ti0.96)O3(BCST) cermaics were investigated. The phase compositions, microstructure, dielectric, ferroelectric and piezoelectric properties of BCST ceramics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), precision impedance analyzer, ferroelectric tester and quasi-static piezoelectric constant testing meter, respectively. The results show that CuO-B2O3(CBO) frit can improve the densification and promote low-temperature sintering of BCST ceramics prepared by a conventional solid-state reaction method. Dense BCST ceramics with CBO can be sintered at temperatures as low as 1175 °C, which is approximately 275 °C less than the sintering temperature of pure BCST. When sintered at 1200 °C, the optimized properties of the BCST ceramics with 0.5 wt% CBO were obtain asε= 1206,d33= 346 pC/N,kP= 0.39, tgδ = 0.009.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 455 ◽  
Author(s):  
Sam Yeon Cho ◽  
Eun-Young Kim ◽  
Sun Yong Kim ◽  
Thuy Linh Pham ◽  
Jin Kyu Han ◽  
...  

We synthesized lead-free piezoelectric (Bi0.5Na0.5-xKx)TiO3 (BNKT) ceramics using a conventional solid-state reaction method. We have investigated the structural and electrical properties of the materials with x = 0.05 to 0.40. The X-ray diffraction (XRD) analysis suggests that the BNKT ceramics show the transition from rhombohedral to tetragonal structure. The ratio of the tetragonal structure increased continuously in accordance with the increasing composition of x. The sample of x = 0.10 showed a similar ratio between the tetragonal and rhombohedral structures. Frequency-dependent dielectric measurements showed a sort of relaxor properties emerged with increasing x composition, this effect may be interpreted in terms of the formation of polar nano-regions (PNRs) in samples. The value of remnant polarization (Pr) decreases rapidly as x increases beyond the point of x = 0.10 from 25.3 μC/cm2 to 5.9 μC/cm2. On the contrary, as for inverse piezoelectric coefficient (d33*), a higher value of d33* (336 pm/V) at x = 0.10, was observed when compared with x = 0.05 (d33* = 51 pm/V). These results can be explained by the formation of PNRs and their variations with the external applied field. We here propose a possible mechanism showing the effects of dipolar defects, which can be resulted from the K ion substitution on (Bi,Na)TiO3 (BNT) ceramics.


2020 ◽  
Vol 42 (5) ◽  
pp. 634-634
Author(s):  
Fares Kahoul Fares Kahoul ◽  
Louanes Hamzioui Louanes Hamzioui ◽  
Abderrezak Guemache Abderrezak Guemache ◽  
Michel Aillerie and Ahmed Boutarfaia Michel Aillerie and Ahmed Boutarfaia

Modified-PZT ceramics with a formula (1-x)Pb(Zr0.53 Ti0.47)O3-xSr(Fe2/3, Nb1/3)O3 (doped with isovalent: Sr2+, acceptor: Fe3+ and Donor: Nb5+ ions) abbreviated as (1-x)PZT-xSFN binary system with varying x (x= 0.02, 0.04, 0.06, 0.08 and 0.10) located near the morphotropic phase boundary (MPB) were prepared by a traditional process in a solid state. All the samples were sintered at a temperature of 1200and#176;C during 2 h. The phase structure, the dielectric and piezoelectric properties of the system were studied. In-phase analysis used X-ray diffraction (XRD) at room temperature indicated that the structure of phase of sintered PZT-SFN ceramics was formed in single-phase with a crystalline structure tetragonal. Raman spectroscopy confirms the presence of this tetragonal phase. The optimum electrical parameters are obtained at 0.94Pb(Zr0.53Ti0.47)O3-0.06Sr(Fe2/3, Nb1/3)O3 system: kp= 66.10 %, d31= 145 pC/N, Qm= 473, tanδ= 1.11 %, and ɛr= 1009.


2018 ◽  
Vol 4 (5) ◽  
pp. 487-491 ◽  
Author(s):  
G. Satyanarayana ◽  
G. Nageswara Rao ◽  
K. Vijaya Babu

Ferrite materials with the general formula Ni0.7Zn0.2Cu0.1Fe1.9M0.1O4 (M=Al and Cr) are synthesized by using the solid state reaction method. X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectra, scanning electron microscope (SEM) dielectric measurements and vibrating sample magnetometer (VSM) techniques are utilized to study the various properties of the synthesized ferrites. XRD analysis confirmed the formation of single phase cubic spinel structure and the crystallite size is calculated by Scherrer’s formula found to be 20.3 and 12.5 nm. The magnetic properties were studied using pulse field hysteresis loop technique at room temperature. The saturation magnetization exhibit 98.71 and 91.69 emu/g for Al3+ and Cr3+ substituted Ni-Zn-Cu ferrites respectively. The magnetic permeability is increasing for chromium substituted compound in the frequency range 100 Hz to 120 MHz and significant modification in DC conductivity is explained on the basis of hopping mechanism.


2011 ◽  
Vol 194-196 ◽  
pp. 109-112
Author(s):  
Min Huang ◽  
Yun Wu Wang

Ceramic samples with the nominal composition (1-x) BaTiO3 + x Ba3Ti2YO8.5 (x = 0 - 0.4) were prepared by the solid-state reaction method. The X-ray diffraction (XRD) analysis and the lattice parameters determination indicate that the samples with x≤ 0.16 exhibit a single phase cubic perovskite structure. When x > 0.16, the system is of biphasic composites, which consist of Ba(Ti0.911Y0.089)O3 and Ba3Ti2YO8.5. The microstructure observation by Scanning Electron Microscopy (SEM) supports the XRD result. For the biphasic composites, the dielectric constant follows the Lichtenecker relation in a wide temperature range.


Author(s):  
Nan Wei ◽  
Tomoaki KARAKI ◽  
Tadashi Fujii

Abstract (K,Na,Li)NbO3-BaZrO3-(Bi,Na)TiO3-x B2O3 (abbreviated as KNLN-BZ-BNT-x B2O3) ceramics were prepared by conventional solid state reaction method. The effects of B2O3 content on dielectric and piezoelectric properties of the KNLN-BZ-BNT ceramics have been studied. Based on the identification by X-ray diffraction (XRD), all the samples show a two-phase coexistence zone consisting of rhombohedral (R) and tetragonal (T) phases. For the ceramics with x = 0.5 wt%, the sintering temperature was observed to reduce from 1200 oC to 940 oC, while the samples maintained a high relative density around 97%. Because of the high densification and large grain size, the dielectric and piezoelectric properties were improved. As a result, the ceramics with x = 0.5 wt% sintered at 940 oC exhibited good properties of d 33 = 197 pC/N, k p= 0.29, tan δ = 0.029 and ε r = 1889, together with a Curie temperature (T C) of 222 oC.


2011 ◽  
Vol 01 (03) ◽  
pp. 351-356 ◽  
Author(s):  
P. PALEI ◽  
P. KUMAR

Lead free (K0.5Na0.5)NbO3 (KNN) ceramics were prepared by conventional solid state reaction route. For single perovskite phase formation, calcination temperature was optimized at 850°C for 6 h, whereas for dense morphology the sintering of the ceramic was carried out at 1120°C for 4 h. X-ray diffraction XRD analysis confirmed the formation of single phase with orthorhombic structure at room temperature. Impedance analysis and AC conductivity studies of the KNN sample was carried out in the temperature range of 703–773 K. Impedance study showed the increase in conducting behavior at higher temperature. The temperature dependence of AC conductivity indicated that the conduction process is due to doubly ionized oxygen vacancies in the higher temperature region.


2012 ◽  
Vol 26 (06) ◽  
pp. 1150039 ◽  
Author(s):  
M. NAVASERY ◽  
S. A. HALIM ◽  
K. P. LIM ◽  
S. K. CHEN ◽  
A. S. ROSLAN ◽  
...  

We synthesized the polycrystalline manganite of La5/8Ca3/8MnO3with three different manganese routes prepared through a solid state reaction method. The effects of the manganese route selection on the structure, electrical transport and magneto-transport properties were examined in this study. The samples were characterized using X-ray diffraction (XRD) and SEM to identify their structure and morphology. XRD analysis confirmed that all samples were in single phase with orthorhombic structure and belonged to the Pnma space group. The average grain sized samples with manganese route of Mn2O3and MnCO3had a grain size of 1.2–8.7 μm and 2–7.5 μm, respectively. For the MnO2route, the sample had a small melt-like shape with higher porosity. The metal–insulator transition temperature, TMI, for LCMO ( Mn2O3), LCMO ( MnO2) and LCMO ( MnCO3) samples were 270 K, 266 K and 258 K, respectively. All the samples showed negative magneto-resistance with significant increase in value near the TMItemperature. The highest CMR (colossal magneto-resistance) ratio was found in LCMO ( Mn2O3), -22.06% at 270 K, followed by -16.69% for LCMO ( MnO2) at 80 K, and 15.2% for LCMO ( MnCO3) at 100 K in a 1 T magnetic field.


Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.


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