scholarly journals Effects of Oxygen Ion Irradiation on PZT Modified Ferroelectric Materials for Space Applications

2016 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Dielectric Constant ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
Ferroelectric Material ◽  
Pyroelectric Coefficient ◽  
Ferroelectric Materials ◽  
Dielectric Constants ◽  
Space Applications ◽  
Oxygen Ion ◽  
Wide Range

Lead magnesium niobate-lead titanate (PMN-PT) is an important and high performance piezoelectric and pyroelectric relaxor material having wide range of applications in infrared sensor devices. Present work studies the fabrication and dielectric characteristics of PMN-PT in the bulk form. The PMN-PT bulk material was prepared in sol-gel method and subsequently irradiated with heavy ion oxygen. The materials were analyzed and determined that the relaxor ferroelectric material indicated changes in its dielectric constant and pyroelectric coefficient after irradiation. Due to the radiation fluent of 1×1016 ions/cm2 , the dielectric constant of the material increased uniformly, while its pyroelectric coefficient showed a sharp increased to the value of 5×10-9 μC/cm2 °C with increase in temperature. Its dielectric constants showed increase in values of 527 μC/cm2 °C at 50°C, 635 μC/ cm2 °C at 60°C and 748 μC/cm2 °C at 70°C. Properties such as the material impedance, admittance and modulus were investigated for changes in properties which became evident after irradiation. In this paper effect of oxygen ion irradiation on the LiTaO3 and two commercial samples BM 300 and BM 941 are also reported and analyzed. All these bulk materials were functional even after irradiation and was showing enhancement in some of the key characteristics of ferroelectric material.

Microwave properties of drilling fluids

Geophysics ◽  
1981 ◽  
Vol 46 (3) ◽  
pp. 322-332 ◽  
Author(s):  
James N. Lange ◽  
Steven S. Shope
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Weight Percent ◽  
Dielectric Constants ◽  
Drilling Fluids ◽  
Nanosecond Pulses ◽  
Microwave Attenuation ◽  
In Situ Conditions ◽  
Wide Range

The application of electromagnetic (EM) techniques to well logging is initiated in an environment dominated by the properties of the drilling fluids. An impulse technique using nanosecond pulses is applied to a coaxial waveguide containing drilling fluids to measure the velocity (dielectric constant ε) and absorption (attenuation coefficient α) of EM impulses. It is the large difference in dielectric constants of water and oil which makes EM propagation techniques attractive for logging. Dielectric properties of some nondispersed drilling fluids (bentonite and attapulgite clays) are found to be largely dependent upon the volume of water present. Both bentonite and attapulgite clays exhibit the same range of dielectric constants (ε = 81 → 75) when the weight percent of clay is increased to 10 percent. In contrast, the microwave attenuations of these two clays are quite different, with that of the bentonite increasing at about 4 times the rate of the attapulgite suspensions. Microwave attenuation measured for a variety of commercial drilling fluids varies over a wide range, with the lignosulfonates the largest (91 dB/m) and oil inverts the smallest (3 dB/m). The oil inverts also have a small dielectric constant (ε = 3 → 6). Temperature dependence of the attenuation for these same drilling fluids is determined in the range from 23 °C to 45 °C to indicate their behavior under in situ conditions.

Diffusion of Strain Induced Defects after Heavy Ion Irradiation

1998 ◽  
Vol 527 ◽  
Author(s):  
G. Aggarwal ◽  
P. Sen
Keyword(s):  
Ion Irradiation ◽  
Resistivity Measurement ◽  
Heavy Ion ◽  
Oxygen Ion ◽  
Internal Surfaces ◽  
New Type ◽  
Cold Rolled ◽  
Recovery Dynamics ◽  
Induced Defects

ABSTRACTWe report study of recovery dynamics, followed by in-situ resistivity measurement, after 100 MeV oxygen ion irradiation in cold rolled Fe at 300K. Scaling behavior with microstructural density and temperature of sample has been used to establish stress induced defects formed during irradiation as a new type of sink. The dynamics after irradiation has been shown to be due to migration of defects to two types of sinks i.e. stress induced defect as variable sinks and internal surfaces as fixed sinks.

Magnetic nanoparticles for space applications

2004 ◽  
Vol 851 ◽  
Author(s):  
S. K. Sharma ◽  
Ravi Kumar ◽  
S. N. Dolia ◽  
V. V. Siva Kumar ◽  
Mahavir Singh
Keyword(s):  
Saturation Magnetization ◽  
Surface Defects ◽  
Ion Irradiation ◽  
Spinel Ferrite ◽  
Space Station ◽  
Heavy Ion ◽  
Space Applications ◽  
Potential Applications ◽  
Powder Samples ◽  
Radiation Resistant

ABSTRACTRadiation resistant ferrite materials have potential applications in space station. Mg-Mn spinel ferrite was choosen for this study because of its radiation resistance and potential for use as an insulator in radiation environments. The radiation damage expected in these environments can be quickly and conveniently simulated using ion irradiation. The results of swift heavy ion irradiation induced modifications in the magnetization behavior of the Mg-Mn ferrite nanoparticles have been investigated using 100 MeV Ni8+ ion irradiation. To ensure the singlephase spinel structure of the system powder x-ray diffraction patterns has been performed. The powder samples were irradiated at three different fluences in the range 1×1012-5×1013 ions/cm2. Isothermal dc magnetization studies have been performed using SQUID and vibration sample magnetometer (VSM) on the pristine as well as on the irradiated samples at 20 K and 300 K. With irradiation saturation magnetization remains almost constant with ions irradiation. The coercivity values of the materials decreased about 5% with the fluence 1×1013 ions/cm2 as compare to the pristine nanoparticles. The results have been explained on the basis of the existence of surface defects produced by swift heavy ions, which generate orientational disorder of surface spins. The behavior of saturation magnetization with irradiations makes these nanoparticles suitable for memory devices in the space research.

Preparation and Properties of Polyisoimides as a Highly Dimensionally Stable Polyimide Precursor with Low Dielectric Constant

1997 ◽  
Vol 9 (3) ◽  
pp. 333-344 ◽  
Author(s):  
Hiroshi Seino ◽  
Osamu Haba ◽  
Amane Mochizuki ◽  
Masahiro Yoshioka ◽  
Mitsuru Ueda
Keyword(s):  
Dielectric Constant ◽  
Dielectric Constants ◽  
Isomerization Reaction ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Fluorinated Polyimides ◽  
Wide Range ◽  
Biphenyltetracarboxylic Dianhydride ◽  
Polyimide Precursor ◽  
Dipolar Aprotic Solvents

Fluorinated polyimides (PIs) with low dielectric constant and high dimensional stability have been developed using polyisoimides (PIIs) as a polyimide precursor. The PIIs were prepared by the ring-opening polyaddition of the dianhydrides pyromellitic dianhydride, biphenyltetracarboxylic dianhydride and 4, 4′-hexafluoropropylidenedi(phthalic anhydride) with the diamines 2, 2′-dimethylbenzidine and 2, 2′-bis(trifluoromethyl)benzidine, followed by treatment with trifluoroacetic anhydride/triethylamine or dicyclohexylcarbodiimide in N;N-dimethylacetamide. The PIIs were soluble in a wide range of solvents including dipolar aprotic solvents, cyclohexanone and tetrahydrofuran at room temperature, and easy to convert to corresponding PIs by high thermal treatment. The resulting PIs showed low dielectric constants of less than 3 at 1 MHz as well as low CTEs. Furthermore, during the isomerization reaction, migration of copper in the PI film was hardly observed.

Ferroelectric nanocomposite with high dielectric constants

2002 ◽  
Vol 755 ◽  
Author(s):  
Mai T.N. Pham ◽  
B.A. Boukamp ◽  
H.J.M. Bouwmeester ◽  
D.H.A. Blank
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Ferroelectric Material ◽  
Metallic Phase ◽  
Dielectric Constants ◽  
Effective Dielectric Constant ◽  
X Ray Diffraction ◽  
Non Volatile Memory ◽  
Colloidal Method ◽  
High Dielectric

ABSTRACTComposites between ferroelectric material and a dispersed metal phase are of great interest due to the improvement in dielectric properties for such applications as high capacitance capacitors, non-volatile memory, ect. Using a colloidal method, Pt particles with a size of 3–5 nm were dispersed homogeneously in a PZT (PbZr0.53Ti0.43O3) matrix. No unwanted reaction phase between PZT and Pt during sintering at 1150 °C could be detected by X-ray diffraction. Electrical properties were investigated by impedance spectroscopy measurement. The effective dielectric constant increased remarkably as a power function of Pt volume content and can be described by the percolation theory. At 25 vol.% of Pt the dielectric constant of the composite is 4 times larger than that of pure PZT. The temperature dependence of the electrical properties is also influenced by the metallic phase fraction.

Studies in the Vulcanization of Rubber. V. Dielectric Constant and Power Factor of Vulcanized Rubber

1932 ◽  
Vol 5 (3) ◽  
pp. 367-383
Author(s):  
Donald W. Kitchin
Keyword(s):  
Dielectric Constant ◽  
Sulfur Content ◽  
Power Factor ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Low Dielectric ◽  
Vulcanized Rubber ◽  
Wide Range ◽  
Hard State ◽  
Critical Experiment

Abstract 1. Power factor and dielectric constant data have been given for vulcanized rubber samples tested over a wide range of composition, temperature, and frequency. 2. The real identity of the agents responsible for the peculiar dielectric behavior is not known. It seems probable that these agents are the rubber-sulfur molecules themselves. because the effects increase, under proper conditions, directly with per cent combined sulfur. 3. The effect of increasing sulfur content on the dielectric behavior is complex; it modifies not only these supposed agents themselves, but also the stiffness of their environment. Moreover, at a given sulfur content the agents are not identical but differ widely in relaxation time, and therefore in ability to respond; and with progressive addition of sulfur, the rubber does not increase continuously in stiffness, but, at a composition which depends on the temperature, passes rather abruptly from a soft to a hard state. 4. The temperature at which the transition from one state to the other occurs increases almost linearly with the sulfur content from −90° to +90° C. 5. In the soft state the behavior of vulcanized rubber with respect to compressibility, thermal expansion, dielectric constant, and power factor, and probably other properties, resembles that of a viscous liquid; in the hard state, that of a solid. 6. Rubber with less than 2 per cent combined sulfur shows low dielectric constant and power factor over the whole temperature and frequency range investigated; hard rubber, only at room temperature, where its rigidity restricts the response to the field. 7. Hard rubber, although not an electret, can hold an electric charge for 24 hours or more. The low dielectric constants of high-sulfur rubber samples found in measurements with a ballistic galvanometer were due to the disparity between its period of about one second and the long discharge periods of the samples. This led to the idea of dipole compensation shown to be incorrect by the high temperature results. 8. At temperatures sufficiently high to permit free response, the dielectric constant increases with sulfur content over the whole range. 9. If a dipole mechanism is involved, addition of sulfur to more than half the double bonds does not cause the dipole moment of the molecules to vanish owing to compensation. 10. The power factor of vulcanized rubber sheets decreases on stretch. 11. The data neither prove nor disprove a dipole mechanism. A critical experiment to settle this question is still wanting.

Structural Features and Microwave Properties of Ba0.5Sr0.5TiO3 Films Grown on Sapphire Substrates

2007 ◽  
Vol 124-126 ◽  
pp. 1829-1832
Author(s):  
Kwang Hwan Cho ◽  
Jong Yoon Ha ◽  
Chong Yun Kang ◽  
Ji Won Choi ◽  
Young Pak Lee ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Phase Shifter ◽  
Impedance Matching ◽  
Rf Sputtering ◽  
Structural Features ◽  
Ferroelectric Materials ◽  
Tunable Filter ◽  
Sapphire Substrates ◽  
Wide Range ◽  
Bst Films

The change in dielectric constant of ferroelectric materials as a function of electric field is the key to wide range of microwave application such as tunable filter, impedance matching network, and phase shifter. In this study, ferroelectric Ba0.5Sr0.5TiO3 (BST) films were grown on r-cut sapphire and polycrystalline sapphire (poly-sapphire) substrates by RF sputtering. The results of comprehensive structural diagnostics of the films are correlated with the dielectric constant and dielectric loss of a co-planar BST varactor, measured at a frequency range of 1~3 GHz. Textured BST films approximately 500 nm thick, grown on r-cut sapphire substrates, are characterized by high dielectric constant ≥ 650. However, polycrystalline BST films, grown on poly-sapphire substrates, are less strained, having dielectric constant range of 430 ~ 640.

THE DIELECTRIC CONSTANTS OF HYDROGEN PEROXIDE-ETHER AND HYDROGEN PEROXIDE-WATER-ETHER MIXTURES

1931 ◽  
Vol 4 (4) ◽  
pp. 322-329 ◽  
Author(s):  
E. P. Linton ◽  
O. Maass
Keyword(s):  
Hydrogen Peroxide ◽  
Dielectric Constant ◽  
Mole Fraction ◽  
Unit Volume ◽  
Dielectric Constants ◽  
Pure Hydrogen ◽  
Water Mixture ◽  
Mixture Rule ◽  
Wide Range ◽  
Molecular Fraction

The dielectric constants of solutions of hydrogen peroxide and of hydrogen peroxide-water mixtures in ether have been determined over a wide range of concentrations. It was shown: (a) that the dielectric constant of hydrogen peroxide in ether is proportional to the amount of hydrogen peroxide per unit volume, and (b) that the variation of the dielectric constant with mole fraction was proportional to the dielectric constant of the solution examined, so that the logarithm of the dielectric constant varies in a linear way with the molecular fraction. By this means the dielectric constant of pure hydrogen peroxide at 0 °C. was found to be 93.7. It has been shown that hydrogen peroxide-water mixture has a higher dielectric constant than either constituent. The densities of ether-hydrogen peroxide solutions were measured and a maximum aberration from the mixture rule found at a 1:1 concentration.

scholarly journals Heavy-Ion Microbeams for Biological Science: Development of System and Utilization for Biological Experiments in QST-Takasaki

2019 ◽  
Vol 3 (2) ◽  
pp. 13 ◽  
Author(s):  
Tomoo Funayama
Keyword(s):  
Radiation Effects ◽  
Cultured Cells ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
Biological Research ◽  
C Elegans ◽  
Beam Focusing ◽  
Wide Range ◽  
Vertical Beam ◽  
Beam Collimation

Target irradiation of biological material with a heavy-ion microbeam is a useful means to analyze the mechanisms underlying the effects of heavy-ion irradiation on cells and individuals. At QST-Takasaki, there are two heavy-ion microbeam systems, one using beam collimation and the other beam focusing. They are installed on the vertical beam lines of the azimuthally-varying-field cyclotron of the TIARA facility for analyzing heavy-ion radiation effects on biological samples. The collimating heavy-ion microbeam system is used in a wide range of biological research not only in regard to cultured cells but also small individuals, such as silkworms, nematode C. elegans, and medaka fish. The focusing microbeam system was designed and developed to perform more precise target irradiation that cannot be achieved through collimation. This review describes recent updates of the collimating heavy ion microbeam system and the research performed using it. In addition, a brief outline of the focusing microbeam system and current development status is described.

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