scholarly journals Comparative Study on Structural, Electrical Transport and Magnetic Properties of Cr-Doped in Charge-Ordered Pr0.75Na0.25Mn1-Xcrxo3 and Nd0.75Na0.25Mn1-Ycryo3 Manganites

2018 ◽  
Vol 7 (4.30) ◽  
pp. 76
Author(s):  
Rabiatul Adawiyah Zawawi ◽  
Nurul Nasuha Khairulzaman ◽  
Suhadir Shamsuddin ◽  
Norazila Ibrahim
Keyword(s):  
Magnetic Properties ◽  
Electrical Transport ◽  
Ac Susceptibility ◽  
Parent Compound ◽  
Double Exchange ◽  
Xrd Analysis ◽  
Ferromagnetic Transition ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Lower Temperature

Cr doping in charge-ordered Pr0.75Na0.25Mn1-xCrxO3 and Nd0.75Na0.25Mn1-yCryO3 have been synthesized using conventional solid-state method to investigate its effect on structural, electrical transport and magnetic properties. X-ray diffraction (XRD) analysis for both compounds showed that the samples were crystallized in an orthorhombic structure with Pnma group. The unit cell volume value      decrease as the Cr-doped increased indicating the possibility of Mn3+ ion was replaced by Cr3+ due to the different of ionic radius. The temperature dependence of electrical resistivity showed an insulating behavior down to the lower temperature the both parent compound (x = 0 and y = 0). Successive substitution of Cr at Mn-site in Pr0.75Na0.25Mn1-xCrxO3 manganites induced the metal-insulator (MI) transition temperature around TMI~120 K and TMI~122 K for x = 0.02 and x = 0.04 samples respectively suggestively due to the enhancement of double-exchange (DE) mechanism as a result of suppress the CO state. Analysis of resistivity data of dlnρ/dT-1 vs. T in Nd0.75Na0.25Mn1-yCryO3 manganite, showed a peak around 210 K and 160 K for y = 0 and 0.02 samples respectively while no peak was observed for y = 0.05 sample indicate the charge-ordered (CO) weakened. AC susceptibility, χ’ measurements in Pr0.75Na0.25Mn1-xCrxO3 exhibits paramagnetic to ferromagnetic-like with curie temperature, TC increases from 132 K for x = 0.02 to 141 K for x = 0.04 with Cr content indicate the suppression of CO state meanwhile in Nd0.75Na0.25Mn1-yCryO3 showed paramagnetic to anti-ferromagnetic transition as Neel temperature TN increases from 115 K for y = 0.02 to 125 K for y = 0.05.

scholarly journals Effect Of Co3+ Substitution on Electro-Magnetic Properties of Pr¬0.75¬Na¬0.25¬mno¬3 ¬and Nd¬0.75¬Na¬0.25¬mno¬3¬ Manganites

2018 ◽  
Vol 7 (4.30) ◽  
pp. 389
Author(s):  
Nurhabibah Nabilah Ab Mannan ◽  
Sufia Aqilah Razali ◽  
Suhadir Shamsuddin ◽  
Mohamad Zaky Noh ◽  
Zakiah Mohamed
Keyword(s):  
Magnetic Properties ◽  
Electrical Transport ◽  
Resistivity Measurement ◽  
Charge Order ◽  
Solid State Reaction Method ◽  
Diffraction Measurement ◽  
Ferromagnetic Transition ◽  
Antiferromagnetic Transition ◽  
X Ray Diffraction ◽  
Electro Magnetic

This paper reports influences of cobalt (Co) substituted at Mn-site of Pr­0.75­Na­0.25Mn1-xCo­x­O­3 and Nd0.75Na0.25Mn1-yCoyO3 on structure, electrical transport and magnetic properties. All of the samples were prepared via standard solid state reaction method. X-ray diffraction measurement indicates that all samples were crystallized in an orthorhombic structure (space group Pnma). Resistivity measurement displays the x = 0 sample manifests an insulator behavior while metal-insulator transition was found at 108 K and 84 K for x = 0.02 and 0.05 respectively for Pr­0.75­Na­0.25Mn1-xCo­x­O­3. On the other hand, all of the samples for Nd0.75Na0.25Mn1-yCoyO3 showed insulator behavior down to low temperature and analysis of the resistivity change with respect to temperature, dlnρ/dT-1 versus T reveals a slope changes of resistivity have been recorded. Two obvious peaks were recorded from the analysis for y = 0.02 and 0.05 which can be suggested to the existence of charge order transition at the vicinity. For magnetic properties, x = 0 sample showed a paramagnetic-antiferromagnetic transition and further substitution of Co, x = 0.02 and 0.05, induce the paramagnetic-ferromagnetic transition and antiferromagnetic arrangement respectively. Meanwhile, further substitution of Co, y = 0.02 and 0.05 indicate antiferromagnetic transition with increasing T­N­­­ as Co increased.

STUDY OF ELECTRICAL TRANSPORT AND AC SUSCEPTIBILITY IN LaMn1-xCuxO3

2005 ◽  
Vol 19 (06) ◽  
pp. 317-330 ◽  
Author(s):  
MANORANJAN KAR ◽  
S. RAVI
Keyword(s):  
Transition Temperature ◽  
Electrical Transport ◽  
Small Polaron ◽  
Ac Susceptibility ◽  
Ferromagnetic Transition ◽  
X Ray Diffraction ◽  
Polaron Hopping ◽  
Phase Form ◽  
Resistivity Data ◽  
Diffraction Patterns

LaMn 1-x Cu x O 3 compounds have been prepared in single phase form for x = 0 to 0.30. X-ray diffraction patterns recorded at room temperature could be mostly refined using Pbnm space group. Paramagnetic-to-ferromagnetic transitions have been observed up to x = 0.30, from ac susceptibility measurements. Metal–insulator transition in the vicinity of ferromagnetic transition temperature has been observed for x = 0.05 and the resistivity data in the metallic region could be explained in terms of electron–electron and electron–magnon scattering mechanisms. Further increase in Cu-doping beyond x = 0.05 leads to systematic decrease in ferromagnetic transition temperature and ultimately ferromagnetism is destroyed for x = 0.40. The resistivity data of all samples except x = 0.05 exhibit semiconducting behaviors and they could be mostly explained using the adiabatic small polaron hopping model.

scholarly journals Impact of Ag-Doped on the Ferromagnetic-Metallic Transition in Pr0.75Na0.25mno3 Manganites

2018 ◽  
Vol 7 (4.30) ◽  
pp. 68
Author(s):  
N Khairulzaman ◽  
N Ibrahim ◽  
S Shamsuddin
Keyword(s):  
Single Phase ◽  
Ac Susceptibility ◽  
Double Exchange ◽  
Xrd Analysis ◽  
Charge Ordering ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Jahn Teller ◽  
Jahn Teller Effect

Monovalent doped Pr0.75Na0.25-yAgyMnO3 (y = 0–0.10) manganite have been investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) as well as DC electrical resistivity and AC susceptibility measurement to clarify the influence of Ag- doped on charge ordering (CO) state. XRD analysis revealed all samples consists of essentially single phase and crystallized in an orthorhombic structure with space group Pnma. SEM images of Pr0.75Na0.25-yAgyMnO3 compound shows the successful substitution of Ag+ ions with the enhancement of the grains boundaries and sizes as well as the compaction of particles. On the other hand, resistivity and susceptibility measurements showed that the y = 0 sample exhibits insulating behavior and anti-ferromagnetic. Interestingly, the ferromagnetic-metallic transition was observed for y = 0.05 due to the revival of double-exchange (DE) mechanism as a result of weakening the Jahn-Teller effect which caused the CO state to be weakened. However, increasing of Ag-doped up to y = 0.10 induce back its transition into anti-ferromagnetic insulating behavior suggestively due to the weakening of DE mechanism.

Effect of Fe Doping on the Structural, Electrical and Magnetic Properties of Perovskite La0.7Ca0.3Mn1-xFexO 3 (X = 0, 0.01, 0.03 and 0.05)

2021 ◽  
Vol 317 ◽  
pp. 10-16
Author(s):  
Nor Azah Nik-Jaafar ◽  
Roslan Abd-Shukor ◽  
Muhammad Aizat Kamarudin
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Xrd Analysis ◽  
Ferromagnetic Transition ◽  
Fe Doping ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Electrical And Magnetic Properties ◽  
Insulator Metal Transition ◽  
Fe Substitution

The effect of Fe-substitution at the Mn-site in La0.7Ca0.3Mn1-xFexO3 (x = 0, 0.01, 0.03 and 0.05) on its structure, electrical and magnetic properties has been studied. These properties were investigated via X-ray diffraction (XRD) analysis, temperature-dependent resistance measurements and temperature-dependent AC magnetic susceptibility measurements. XRD analysis showed all samples are single phase materials. Temperature dependent resistance measurements between 30–300 K showed all samples to undergo insulator-metal transition as temperature decreases. Increase in Fe doping for x = 0, 0.01, 0.03 and 0.05 caused the transition temperature TIM to decrease from 257 K, 244 K, 205 K and 162 K respectively. The magnetic susceptibility measurements showed the samples to exhibit paramagnetic to ferromagnetic transition as temperature decreased. Increase in Fe substitution x at the Mn-site progressively decreased the Curie temperature TC from 250 K at x = 0 to 170 K at x = 0.05.

Study of Phase Purity of Eu2-xCexCuO4 Synthesized by Solid State Method without Annealing Process

2021 ◽  
Vol 1028 ◽  
pp. 62-67
Author(s):  
Yuyu R. Tayubi ◽  
Yati Maryati ◽  
Muhammad Abdan Syakuur ◽  
Diba G Auliya ◽  
Togar Saragi ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Xrd Analysis ◽  
Annealing Process ◽  
Excess Oxygen ◽  
Heating Process ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Solid State Method ◽  
Phase Purity ◽  
High Phase

The samples of Eu2-xCexCuO4 (ECCO) with x = 0.10, 0.13, 0.17 and 0.20 have been synthesized by the solid reaction method without annealing process [1,2]. Each sample is covered by CuO powder to prevent excess oxygen entering the sample during heating process. The purpose of this research is to study the crystal structure and the level of phase purity in ECCO samples in the wide ranges of doping concentration of ECCO. The results of X-ray diffraction (XRD) characterization showed that the main peaks of T' tetragonal structure were observed in all samples. From the XRD analysis, it was found that the level of phase purity of ECCO was 100 % for x = 0.10, 100 % for x = 0.13, 79.5.% for x = 0.17, and 79.1 % for x = 0.20, respectively. For the lattice constant, it is found that both a and c-axis did not change significantly as the concentration increased. These results show that the synthesis method with CuO covering has succeeded in synthesizing materials with high phase purity although the constants do not change significantly when the concentration increased. However, there are some impurity phases found in high concentration of x that is probably due to the existence of excess oxygen, which was not fully absorbed by CuO Covering.

Synthesis and luminescence properties of the red phosphor CaZrO3:Eu3+ for white light-emitting diode application

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Junli Huang ◽  
Liya Zhou ◽  
Yuwei Lan ◽  
Fuzhong Gong ◽  
Qunliang Li ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Average Diameter ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Light Region

AbstractEu3+-doped CaZrO3 phosphor with perovskite-type structure was synthesized by the high temperature solid-state method. The samples were characterized by X-ray diffraction, scanning electron microscopy, fluorescence spectrophotometer and UV-vis spectrophotometer, respectively. XRD analysis showed that the formation of CaZrO3 was at the calcinations temperature of 1400°C. The average diameter of CaZrO3 with 4 mol% doped-Eu3+ was 2µm. The PL spectra demonstrated that CaZrO3:Eu3+ phosphor could be excited effectively in the near ultraviolet light region (397 nm) and emitted strong red-emission lines at 616 nm corresponding to the forced electric dipole 5 D 0 → 7 F 2 transitions of Eu3+. Meanwhile, the light-emitting diode was fabricated with the Ca0.96ZrO3:Eu0.043+ phosphor, which can efficiently absorb ∼ 400 nm irradiation and emit red light. Therefore Ca0.96ZrO3:Eu0.043+ may have applications for a near ultraviolet InGaN chip-based white light-emitting diode.

Microwave Sintered Porous Mullite Composite

2012 ◽  
Vol 512-515 ◽  
pp. 382-385
Author(s):  
Xu Qin Li ◽  
Xin Zhang ◽  
Rui Zhang ◽  
Bing Bing Fan
Keyword(s):  
Grain Growth ◽  
Microwave Plasma ◽  
Microwave Sintering ◽  
Xrd Analysis ◽  
High Energy ◽  
Volume Density ◽  
X Ray Diffraction ◽  
Porous Mullite ◽  
Lower Temperature ◽  
Porosity Detection

In order to aviod much high energy and CO2 generation. Microwave sintering (MS) is always carried out to prepare refractory. In this work，MS was proposed to sinter mullite composite. An insulation structure based on hybrid heating mode was well designed with the wall of high-aluminum refractory and the aided heaters of SiC. The sintered samples under different sintering processing were characterized by appearent porosity detection and volume density. Phase composition was investigated by X-ray Diffraction (XRD) analysis. Surface and fracture Flied Emission Scanning Electron Microscopy (FESEM) was applied to observe pore distribution and grain growth. Sintering profile was provided in this work. It was found that mullite composite could be prepared within 1h at relative lower temperature around 1300°C. Compared with samples prepared by convitional sintering (CS), MS samples presented better densification and more uniform grain growth. Microwave plasma phenomena was explored inside MS samples, however, not found in CS ones.

Synthesis of Ultrafine MgAl2O4 Powders by Nitrate-Citrate Sol-Gel Combustion Process

2008 ◽  
Vol 368-372 ◽  
pp. 407-408
Author(s):  
Long Chen ◽  
Qi Zhang ◽  
Wen Ping Chen ◽  
Yao Gang Li ◽  
Yan Mo Chen ◽  
...  
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Xrd Analysis ◽  
Transmission Electron Microscopy Image ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Microscopy Image ◽  
Gel Combustion ◽  
Lower Temperature

Ultrafine MgAl2O4 powders were synthesized by a nitrate-citrate sol-gel combustion process using Al(NO3)3·9H2O, Mg(NO3)2·6H2O and C6H8O7·H2O as initial materials. The result of X-ray diffraction (XRD) analysis indicated that single-phase MgAl2O4 powder could be obtained at 850 oC, which is much lower than that needed in solid-state reactions. Transmission electron microscopy image showed that the as-prepared powder was in the nano scale and little agglomerate exited. It is concluded that this process need shorter time, lower temperature, and simple equipments.

STUDY OF STRUCTURAL, ELECTRICAL TRANSPORT AND MAGNETIC PROPERTIES IN La1-xAgxMnO3 COMPOUNDS

2004 ◽  
Vol 18 (05n06) ◽  
pp. 221-231 ◽  
Author(s):  
MANORANJAN KAR ◽  
S. RAVI
Keyword(s):  
Magnetic Field ◽  
Electrical Transport ◽  
Single Phase ◽  
Ac Susceptibility ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Phase Form ◽  
X Ray ◽  
Maximum Value

X-ray diffraction, electrical resistivity and ac susceptibility measurements have been carried out on La 1-x Ag x MnO 3 compounds for x=0.05 to 0.30. These samples are found to be in single phase form with [Formula: see text] space group and with typical lattice parameters a=b=5.524Å and c=13.349Å for x=0.05 sample. The Mn–O–Mn bond angles and variance, σ2 are found to increase with doping. Metal-insulator transitions in the temperature range 254 to 259 K have been observed. These materials exhibit paramagnetic to ferromagnetic transitions in the vicinity of metal-insulator transition temperatures. The paramagnetic susceptibility could be analyzed using Curie–Weiss law. All the above samples exhibit colossal magneto-resistivity and its maximum value is found to be 73% for x=0.15 sample at 50 kOe magnetic field.

Reaction Process of Al-TiO2-C-Ti-Fe Multiphase System during Combustion Synthesis

2007 ◽  
Vol 336-338 ◽  
pp. 2340-2343 ◽  
Author(s):  
Song He Meng ◽  
Xing Hong Zhang ◽  
Wei Feng Zhang
Keyword(s):  
Intermetallic Compounds ◽  
Xrd Analysis ◽  
Reaction Process ◽  
Multiphase System ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Reaction Characteristics ◽  
Lower Temperature ◽  
Kinetics Of

The reaction process and kinetics of Al-TiO2-C-Ti-Fe system were investigated by differential scanning calorimetry (DSC) analysis, X-ray diffraction (XRD) analysis and scanning electron microscope (SEM). In order to obtain the information of reaction process for complicated system, the reaction characteristics of Al-TiO2, Al-TiO2-C and Al-TiO2-C-Ti systems are explored firstly. The results show that the reaction process varies with temperature in Al-TiO2-C-Ti-Fe system. At the lower temperature, the dominating reaction in Al-TiO2-C-Ti-Fe system is that between Al and Ti, Al and Fe, and so TiAlx, FeAlx, and Ti2Fe intermetallic compounds form. With the temperature increasing, the intermetallic compounds are decomposed. Then the decomposed Ti and Al react with C and TiO2 respectively and the stable TiC, Al2O3 and Fe three phases form in the final product.

Sign in / Sign up

Export Citation Format

Share Document