scholarly journals Synthesis of holmium orthoferrite nanoparticles by the co-precipitation method at high temperature

10.30544/612 ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 321-329
Author(s):  
Nguyen Anh Tien ◽  
Truong Chi Hien ◽  
Bùi Xuân Vương
Keyword(s):  
Remanent Magnetization ◽  
Single Phase ◽  
Aqueous Ammonia ◽  
Ammonia Solution ◽  
Precipitation Method ◽  
Aqueous Ammonia Solution ◽  
Paramagnetic Materials ◽  
Co Precipitation ◽  
Hydrolysis Of ◽  
Maximum Field

Holmium orthoferrite HoFeO3 nanoparticles were synthesized by a simple co-precipitation method via the hydrolysis of Ho (III) and Fe (III) cations in boiling water with 5% aqueous ammonia solution. After annealing the precipitate at 750 and 850 °C for 1 hour, the single-phase HoFeO3 product formed with particle size < 50 nm. The synthesized nanopowders are paramagnetic materials with remanent magnetization Mr < 0.01 emu·g-1, the coercive force Hc = 20÷21 Oe, and magnetization Ms ~ 2.73 emu·g-1 at 300 K in a maximum field of 16,000 Oe.

scholarly journals Crystal structure, optical and magnetic properties of PrFeO3 nanoparticles prepared by modified co-precipitation method

2020 ◽  
Vol 14 (4) ◽  
pp. 355-361
Author(s):  
Anh Nguyen ◽  
Ngoc Nguyen ◽  
Irina Mittova ◽  
Nikolai Perov ◽  
Valentina Mittova ◽  
...  
Keyword(s):  
Particle Size ◽  
Single Phase ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Average Particle ◽  
Strong Adsorption ◽  
Different Temperatures ◽  
Paramagnetic Materials ◽  
Co Precipitation ◽  
Potential Use

In this work, PrFeO3 nanoparticles were synthesized by modified co-precipitation method and annealed at different temperatures up to 850?C. The annealed PrFeO3 nanoparticles have single phase orthorhombic structure and the average particle size of 25-30 nm. Due to the very small particle size the prepared PrFeO3 nanoparticles are capable of being used as photocatalyst materials thanks to their strong adsorption bands at 230-400 nm and 400-800 nm observed from the UV-Vis spectra. Additionally, the PrFeO3 nanoparticles are paramagnetic materials with Hc ~ 10Oe and Mr ~ 0. These findings demonstrate their potential use not only as photocatalysts, but also as magnetic materials.

scholarly journals Optical and magnetic properties of orthoferrite NdFeO3 nanomaterials synthesized by simple co-precipitation method

2021 ◽  
Vol 23 (4) ◽  
pp. 600-606
Author(s):  
Pham Thi Hong Duyen ◽  
Anh Tien Nguyen
Keyword(s):  
Single Phase ◽  
Band Gap Energy ◽  
Hot Water ◽  
Precipitation Method ◽  
High Coercivity ◽  
Ferromagnetic Behavior ◽  
Particle Sizes ◽  
Small Band ◽  
Co Precipitation ◽  
Hydrolysis Of

In this work, orthoferrite NdFeO3 nanomaterials with particle sizes 20-40 nm have been successfully synthesized via a simple co-precipitation method through the hydrolysis of Nd (III) and Fe (III) cations in hot water with 5% NaOH as a precipitating agent. Single-phase NdFeO3 was generated after calcination of the as-prepared powder at 700, 800, and 900 °C for 1 hour. The UV-Vis spectra at room temperature presented strong absorption in the UV-Vis regions (l = 200–400 nm and 400–600 nm) with small band gap energy (Eg = 2.2÷2.5 eV). The obtained NdFeO3 nanomaterials exhibited a hard ferromagnetic behavior with high coercivity (Hc = 600–1600 Oe).

scholarly journals Simple Synthesis of NdFeO3 Nanoparticles By the Co-Precipitation Method Based on a Study of Thermal Behaviors of Fe (III) and Nd (III) Hydroxides

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 219 ◽  
Author(s):  
Tien A. Nguyen ◽  
V. Pham ◽  
Thanh L. Pham ◽  
Linh T. Tr. Nguyen ◽  
I. Ya. Mittova ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Remanent Magnetization ◽  
Hot Water ◽  
Precipitation Method ◽  
Thermal Behaviors ◽  
Simple Process ◽  
Co Precipitation ◽  
Hydrolysis Of ◽  
Perovskite Type

In this study, a nanostructured NdFeO3 material was synthesized via a simple process of the hydrolysis of Nd (III) and Fe (III) cations in hot water with 5% NaOH as a precipitating agent. According to the results of the thermal behaviors of each hydroxide, either containing Fe (III) or Nd (III), the perovskite type of neodymium orthoferrite NdFeO3 was simply synthesized by annealing a mixture of Fe (III) and Nd (III) hydroxides at 750 °C. The nanostructured NdFeO3 was obtained in spherical granules with diameters of around 30 nm. The magnetic properties of the material were a coercive force (Hc) of 136.76 Oe, a remanent magnetization (Mr) of 0.68 emu·g–1, and a saturation magnetization (Ms) of 0.79 emu·g–1.

Kinetics of CO2 absorption in aqueous ammonia solution

2010 ◽  
Vol 4 (5) ◽  
pp. 729-738 ◽  
Author(s):  
Feng Qin ◽  
Shujuan Wang ◽  
Ardi Hartono ◽  
Hallvard F. Svendsen ◽  
Changhe Chen
Keyword(s):  
Aqueous Ammonia ◽  
Ammonia Solution ◽  
Co2 Absorption ◽  
Aqueous Ammonia Solution ◽  
Kinetics Of

scholarly journals Effect of CaO on Phase Composition and Properties of Aluminates for Barium Tungsten Cathode

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1380 ◽  
Author(s):  
Jinglin Li ◽  
Jianjun Wei ◽  
Yongbao Feng ◽  
Xiaoyun Li
Keyword(s):  
Single Phase ◽  
Emission Current Density ◽  
Environmental Stability ◽  
Precipitation Method ◽  
Pulse Emission ◽  
Molar Amount ◽  
Mixture Phase ◽  
Before And After ◽  
Method Effects ◽  
Co Precipitation

6BaO·xCaO·2Al2O3 (x = 0.8, 1.2, 1.6, 2, and 2.2) aluminates were synthesized via a liquid phase co-precipitation method. Effects of the molar amount of CaO on the phase of aluminates before and after melting and their hygroscopic phase, melting properties, environmental stability, evaporation, and emission properties were systematically studied. The results show that with the increase of the molar amount of CaO, the aluminates change from a mixture phase to a single phase of Ba3CaAl2O7, and the diffraction peak shifts to a higher angle. The melted phase of the aluminates changed from a single phase to a mixed phase of Ba5CaAl4O12 and Ba3CaAl2O7. Meanwhile, the comprehensive properties of the aluminates are improved. The weight gain of 6BaO·2CaO·2Al2O3 aluminates is only 10.88% after exposure to air for 48 h; the pulse emission current density of barium tungsten cathodes impregnated with 6BaO·2CaO·2Al2O3 aluminates in the porous tungsten matrix can reach 28.60 A/cm2 at 1050 °C, and the evaporation rate is 2.52 × 10−10 g/(cm2·s).

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).

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