Structural, magnetic and electrical properties of RFeO3 (R= Dy, Ho, Yb & Lu) compounds

2021 ◽  
Author(s):  
Mehrnoush Nakhaei ◽  
Davoud Sanavi Khoshnoud
Keyword(s):  
Dielectric Constant ◽  
Rare Earth ◽  
Electrical Properties ◽  
Sol Gel ◽  
Magnetic Hysteresis ◽  
Combustion Method ◽  
Rare Earth Ion ◽  
Gel Combustion ◽  
Diffraction Patterns ◽  
Magnetic And Electrical Properties

Abstract The nanosized rare earth orthoferrites (RFeO3) with R= Dy, Ho, Yb & Lu were synthesis by sol-gel combustion method. The effects of varying rare earth ion on structural, magnetic and electrical properties of RFeO3 nanoparticles (NPs) have been studied. X-ray diffraction patterns of the prepared samples were in single phase with orthorhombic structure with space group Pbnm. The magnetic hysteresis measurements indicated the decrease in the antiferromagnetic nature of RFeO3 from Dy to Lu that can be ascribed to increasing noncollinear Fe moments because of the structural distortion. The electric hysteresis of these samples exhibited narrow electric field-polarization loops. The frequency response of dielectric constant of RFeO3 explained based on dipole relaxation process and Maxwell-Wagner model. In addition, the temperature dependence of dielectric constant illustrated an anomaly in the vicinity of the Neel temperature of RFeO3 compounds. This occurrence indicate that a coupling exist between magnetic and electric orders.

Electrical investigations of holmium-doped BaTiO3 derived from sol-gel combustion

2010 ◽  
Vol 25 (6) ◽  
pp. 1057-1063 ◽  
Author(s):  
Marin Cernea ◽  
Carmen Galassi ◽  
Bogdan S. Vasile ◽  
Paul Ganea ◽  
Roxana Radu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Remanent Polarization ◽  
Sol Gel ◽  
Combustion Method ◽  
Molar Ratio ◽  
Gel Combustion ◽  
Tan Δ ◽  
Gel Combustion Method ◽  
Structure And Microstructure

Holmium-doped BaTiO3 with composition Ba0.97Ho0.03TiO3 was prepared by sol-gel combustion method. A molar ratio of citrate/nitrate (CA/NO3− = 1.3) was used to prepare nanopowders of (Ba,Ho)TiO3. The structure and microstructure of (Ba,Ho)TiO3 powders and ceramics were investigated. The ceramics exhibit a dielectric constant of about 4400 and dielectric loss (tan δ = 0.267) at 10 Hz, and at the Curie temperature (Tc = 132 °C). The remanent polarization and the coercive field of Ba0.97Ho0.03TiO3 ceramics, at 1 kHz, were Pr = 6 μC/cm2 and EC = 0.75 kV/cm. The dielectric and ferroelectric behavior of the holmium-doped BaTiO3 is influenced by the amphoteric character of Ho3+ ions.

scholarly journals Investigation on microstructure and electrical properties of Bi doping Ca3Co4O9 nanoparticles synthesized by sol-gel process

2018 ◽  
Vol 7 (2.29) ◽  
pp. 31
Author(s):  
Mohammed M A ◽  
Izman Sudin ◽  
Alias Mohd Noor ◽  
Srithar Rajoo ◽  
Uday M B ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Sol Gel ◽  
Combustion Method ◽  
Variable Pressure ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Gel Combustion ◽  
Bi Doping ◽  
Increasing Temperature

In this study, nanoparticles of Bi doped Ca3-xCo4O9 [Ca3-xBixCo4O9 where x=0, 0.2, 0.4 and 0.6] were prepared by sol gel combustion method. The phase structures and microstructures of Bi doped Ca3-xCo4O9 powders preparation were investigated. The microstructural observations of different Bi doped Ca3-xCo4O9 powders were evaluated using X-ray diffraction analysis (XRD) and Variable Pressure Scanning Electron Microscope (VPSEM). The bulk Ca3-xBixCo4O9 samples were fabricated using uniaxial cold pressing technique. Electrical resistivity of bulk Ca3-xBixCo4O9 samples with different doping was measured using four-probe method from 300 to 700°K. The electrical resistivity was found to decrease with increasing temperature for the bulk Ca3-xBixCo4O9 samples. The electrical properties of Ca3-xBixCo4O9 are non-monotonic functions of x. 

scholarly journals Defect Luminescence of Yag Nanopowders and Crystals

2012 ◽  
Vol 49 (4) ◽  
pp. 54-60 ◽  
Author(s):  
L. Grigorjeva ◽  
D. Jankoviča ◽  
K. Smits ◽  
D. Millers ◽  
S. Zazubovich
Keyword(s):  
Rare Earth ◽  
Luminescence Band ◽  
Sol Gel ◽  
Stokes Shift ◽  
Combustion Method ◽  
Low Temperature Combustion ◽  
Rare Earth Ion ◽  
Temperature Combustion ◽  
Luminescence Characteristics ◽  
Defect Luminescence

Defect Luminescence of Yag Nanopowders and Crystals Undoped and rare-earth-ion-doped Y3Al5O12 (YAG) nanopowders are prepared by the sol-gel low-temperature combustion method. The luminescence characteristics of the YAG, YAG: Ce, YAG:Pr, and YAG: Ce/Pr nanopowders are compared with those of the single crystals. The luminescence band peaking around 3.1 eV is complex and excited at about 3.6 eV, 3.9 eV and 4.3 eV. The 3.1 eV emission was peculiar to all the samples studied. The Stokes shift of this band is ~0.5 eV. The decay time of the ~3.1 eV emission at 80 K is ~14 ns and the slower decay (afterglow) components are practically absent. The 3.1 eV luminescence was suggested to arise from different intrinsic lattice defects.

Sign in / Sign up

Export Citation Format

Share Document