EFFECT OF RARE-EARTH (RE = La, Nd, Ce AND Gd) DOPING ON THE PIEZOELECTRIC of PZT(52:48) CERAMICS

2007 ◽  
Vol 21 (26) ◽  
pp. 4549-4559 ◽  
Author(s):  
N. UDOMKAN ◽  
P. LIMSUWAN ◽  
T. TUNKASIRI
Keyword(s):  
Rare Earth ◽  
Preparation Method ◽  
Piezoelectric Materials ◽  
Rare Earth Ions ◽  
Coupling Coefficients ◽  
Pzt Ceramics ◽  
Piezoelectric Coupling ◽  
Piezoelectric Characteristics ◽  
Maximum Permittivity ◽  
Effect Of Doping

The purpose of this research is to study the effect of doping some rare earth ions into PZT(52:48) ceramics. The ferroelectric Pb ( Zr x Ti 1-x) O 3 ceramics are well-known as piezoelectric materials for electro-mechanical transducers such as ultrasonic generator, electronic buzzer, and stress sensor, etc. The highest piezoelectric coupling coefficients as well as maximum permittivity are located near the morphotropic phase boundary (MPB). The region of phase transition between the tetragonal and rhombohedral structures in the Pb ( Zr x Ti 1-x) O 3 ceramic shows very adoptable piezoelectric characteristics due to the phase coexistence phenomena, and exhibits a sensitivity of properties to the preparation method, the composition, the firing temperatures and the kinds of additives. The purpose of this research is to study the effect of doping La , Nd , Ce and Gd into Pb ( Zr 0.52 Ti 0.48) O 3 ceramics prepared by solid state reaction. The properties include microstructure, physical properties, dielectric constant (εr) and piezoelectric properties (kp and Qm) of undoped and La , Nd , Ce and Gd doped PZT ceramics. Several effects, such as firing temperature, grain size and dopants, on the properties of PZT were also studied. The undoped PZT ceramics with Zr/Ti at 52/48 indicated the highest εr=1969 and kp= 0.381 for La doping. Doping with La , Nd , Ce and Gd led to an improvement in the εr but a reduced Qm value. The optimum values of electric properties were found in PZT (52/48) doped La with 10.0 mol% sintered at 1200°C for 2 h.

Finite Element Analysis for Nonlinear Time Dependent Response of Piezoelectric Materials

2012 ◽  
Author(s):  
Amir Sohrabi ◽  
Anastasia Muliana
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Piezoelectric Material ◽  
Nonlinear Response ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
High Electric Field ◽  
Time Dependent ◽  
Coupling Coefficients ◽  
Pzt Ceramics

Piezoelectric materials show nonlinear response under high electric field. In addition, recent experiments showed that the electromechanical coupling coefficients of polarized piezoelectric materials, such as PZT ceramics, change with time, leading to history dependent and hysteretic responses in these materials. In this study, the coupling behavior of piezoelectric material under high electric field is investigated. The electromechanically coupled constitutive equation that accounts for history of mechanical loading and electric field is used for the piezoelectric materials. Effect of high electric field which causes nonlinearity in response of piezoelectric material is modeled by taking the material’s electromechanical coupling coefficients to be dependent on applied electric field and single time integration model is employed to incorporate history-dependent behavior. A continuum finite element with displacement and electric potential degrees of freedom that incorporates nonlinear history dependent effect is developed. Nonlinear finite element solver is formulated by using direct iteration method at element level and recursive iterative method at material (Gaussian) integration points. Nonlinear time-dependent finite element formulation is validated by comparing its response with experimental data on PZT ceramics. History dependent and nonlinear response of PZTs due to electric field and stress is discussed. Developed finite element is capable of modeling behavior of smart structures with piezoelectric sensors and actuators.

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

Structural, Morphological and Magnetic Characterization of Sm-substituted Ni-Zn Ferrite

2020 ◽  
Vol 10 (2) ◽  
pp. 152-156 ◽  
Author(s):  
Muhammad Hanif bin Zahari ◽  
Beh Hoe Guan ◽  
Lee Kean Chuan ◽  
Afiq Azri bin Zainudin
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Saturation Magnetization ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Rare Earth Ions ◽  
Ion Concentration ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Combustion Technique

Background: Rare earth materials are known for its salient electrical insulation properties with high values of electrical resistivity. It is expected that the substitution of rare earth ions into spinel ferrites could significantly alter its magnetic properties. In this work, the effect of the addition of Samarium ions on the structural, morphological and magnetic properties of Ni0.5Zn0.5SmxFe2-xO4 (x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) synthesized using sol-gel auto combustion technique was investigated. Methods: A series of Samarium-substituted Ni-Zn ferrite nanoparticles (Ni0.5Zn0.5SmxFe2-xO4 where x=0.00, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by sol-gel auto-combustion technique. Structural, morphological and magnetic properties of the samples were examined through X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) and Vibrating Sample Magnetometer (VSM) measurements. Results: XRD patterns revealed single-phased samples with spinel cubic structure up to x= 0.04. The average crystallite size of the samples varied in the range of 41.8 – 85.6 nm. The prepared samples exhibited agglomerated particles with larger grain size observed in Sm-substituted Ni-Zn ferrite as compared to the unsubstituted sample. The prepared samples exhibited typical soft magnetic behavior as evidenced by the small coercivity field. The magnetic saturation, Ms values decreased as the Sm3+ concentration increases. Conclusion: The substituted Ni-Zn ferrites form agglomerated particles inching towards more uniform microstructure with each increase in Sm3+ substitution. The saturation magnetization of substituted samples decreases with the increase of samarium ion concentration. The decrease in saturation magnetization can be explained based on weak super exchange interaction between A and B sites. The difference in magnetic properties between the samples despite the slight difference in Sm3+ concentrations suggests that the properties of the NiZnFe2O4 can be ‘tuned’, depending on the present need, through the substitution of Fe3+ with rare earth ions.

scholarly journals Structure, Luminescence, and Magnetic Properties of Crystalline Manganese Tungstate Doped with Rare Earth Ion

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Jae-Young Jung ◽  
Soung-Soo Yi ◽  
Dong-Hyun Hwang ◽  
Chang-Sik Son
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Sintering Temperature ◽  
Luminescent Properties ◽  
Concentration Quenching ◽  
Rare Earth Ions ◽  
Precipitation Method ◽  
Rare Earth Ion ◽  
Co Precipitation ◽  
Quenching Phenomenon

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.

scholarly journals Selective Crystallization of Rare‐Earth Ions into Cationic Metal‐Organic Frameworks for Rare‐Earth Separation

2021 ◽  
Author(s):  
Huajun Yang ◽  
Fang Peng ◽  
Danielle E. Schier ◽  
Stipe A. Markotic ◽  
Xiang Zhao ◽  
...  
Keyword(s):  
Rare Earth ◽  
Metal Organic Frameworks ◽  
Rare Earth Ions ◽  
Selective Crystallization ◽  
Metal Organic
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