| Development of Artificial Y-Type Hexaferrites |
01 MAY 2003 |
2 pages |
| Authors:
C. Vittoria; NORTHEASTERN UNIV BOSTON MA
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 | We have developed a technique to orient particles of Y-type hexaferrite in which the c-axis of the particles are oriented perpendicular to a plane As such, that plane becomes necessarily the easy plane of magnetization. For microwave device application the easy plane of magnetization is chosen as the plane to deposit a metallic microstrip and related circuit patterns. The technique entails the rotation of an external magnetic field in the ... |
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| Exchange Coupling and Spin-Flip Transition of CoFe2O4/alpha-Fe2O3 Bilayered Films |
APR 2001 |
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| Authors:
Tatsuo Fujii; Takuya Yano; Makoto Nakanishi; Jun Takada; OKAYAMA UNIV (JAPAN) DEPT OF APPLIED CHEMISTRY
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 | CoFe2O4/alpha-Fe2O3 (ferrimagnetic/antiferromagnetism) bilayered films were prepared on alpha-Al2O3(102) single-crystalline substrates by helicon plasma sputtering. A well-crystallized epitaxial alpha-Fe2O3(102) layer was formed on the substrate, while CoFe2O4 grown on alpha-Fe2O3(102) was a polycrystalline layer with a (100)-preferred orientation. The alpha-Fe2O3(102) films without CoFe2O4 layers clearly showed a spin-flip transition at about 400 K. The spins aligned perpendicular to the film plane at room temperature changed their direction within the film plane ... |
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| Uncompensated Garnet - A Magnetic Semiconductor |
OCT 1998 |
19 pages |
| Authors:
P. E. Wigen; OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS
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| Ca-substituted YIG single crystal films (Ca:YIG) show p-type conduction while Si or Ge doped YIG garnets (Si:YIG or Ge:YIG) have n-type conduction. Both garnet films maintain their superior magnetic properties of pure YIG, while their electrical resistance approaches that of a semiconductor. Bilayers of Si/Ca doped YIG film were grown as a p/n junction and found to have significant p/n junction diode behavior. However, a voltage of 60 to 80 ... |
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| Uncompensated Garnets: A Magnetic Semiconductor |
09 MAY 95 |
38 pages |
| Authors:
Philips E. Wigen; OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS
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| Yttrium iron garnet (YIG) is a ferrimagnetic oxide, Y3Fe5O12 and a good insulator. When five to ten percent of the Y(3+) is replaced by Ca(2+), an uncompensated state exists. The resulting material has perturbed magnetic properties, semiconducting electrical properties with activation energies from 0.2 to 0.4 eV and resistivities as low as 300 ohms cm at room temperature, and modified optical properties. In the past year the conductivity studies have ... |
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| Uncompensated Garnets: A Magnetic Semiconductor |
09 MAY 95 |
36 pages |
| Authors:
Philip E. Wigen; OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS
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| Yttrium iron garnet (YIG) is a ferrimagnetic oxide, Y3Fe5O12 and a good insulator. When five to ten percent of the Y(3+) is replaced by Ca(2+), an uncompensated state exists. The resulting material has perturbed magnetic properties, semiconducting electrical properties with activation energies from 0.2 to 0.4 eV and resistivities as low as 300 ohm cm at room temperature, and modified optical properties. In the past year the conductivity studies have ... |
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| Non-Magnetic Alloy. |
31 JAN 1995 |
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| Authors:
Joseph L. Abita; DEPARTMENT OF THE NAVY WASHINGTON DC
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| A non-magnetic alloy of a volume Vcu of copper and a volume Vmn of manganese Vmn/Vcu is made equal to - Xcu/Xmn where Xcu is the susceptibility of the copper and Xmn is the susceptibility of the manganese. Vmn/Vcu is experimentally predicted to be 1.04 percent by volume. The present invention relates to a non-magnetic alloy and method for making the non-magnetic alloy. Most materials are magnetic to some ... |
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| Non-Reciprocal Superconducting Microwave Devices |
09 SEP 1994 |
5 pages |
| Authors:
Erwin Belohoubek; Alberto Pique; Steven Green; Venky Venkatesan; NEOCERA INC COLLEGE PARK MD
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| One of the major issues revolving around high temperature superconducting (HTS) microwave technology is that, while researchers have applied it to components of various systems, far fewer integrated systems have been designed; such integrated designs are essential for HTS technology to be successfully implemented for practical applications. A variety of HTS microwave components (such as filters and delay lines) have been demonstrated that perform better, weigh less, and occupy less ... |
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| Experimental Study of Location and Identification of Ferrous Spheroids Using a 'Smart' Total Field Magnetometer |
JAN 93 |
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| Authors:
John E. McFee; Robert Ellingson; Yogadhish Das; DEFENCE RESEARCH ESTABLISHMENT SUFFIELD RALSTON (ALBERTA)
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| A microprocessor-controlled magnetometer which accurately locates and identifies compact ferrous objects in real-time is described. The person- portable instrument consists of a cart-mounted cesium magnetometer, optical encoder, microcontroller, interface and laptop computer. The instrument guides the operator to collect simultaneous magnetic field and position data in a horizontal plane above an object. Custom algorithms estimate location and dipole moment and use the latter to classify the object. Data collection takes ... |
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| Electromagnetic Interactions in High-Speed Integrated Electronic Circuits. |
31 MAR 1989 |
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| Authors:
Dennis P. Nyquist; MICHIGAN STATE UNIV EAST LANSING DIV OF ENGINEERING RESEARCH
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| The objective of this research was to investigate electromagnetic interactions among components within microstrip-based circuits fabricated adjacent to the layered surround characteristic of a high-speed MMIC environment. EM fields maintained by currents immersed in layered dielectric/ferrimagnetic media are exploited to study the complete propagation-mode spectrum of microstrip lines and their interactions with the coupled microstrip devices which they interconnect. Topics studied include: (1) electromagnetics of layered dielectric/ferrimagnetic media; (2) mathematical ... |
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| Analysis and Computer Studies of Magnetostatic Wave Transducers |
DEC 1982 |
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| Authors:
I. Jacob Weinberg; LOWELL UNIV MA
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| We here present the analysis and computer program for obtaining the dispersion relation, group delay, magnetostatic wave power, radiation resistance, radiation reactance and insertion loss for forward volume waves and backward volume waves. Included are the consideration of ground planes, apodization of the fundamental mode, multistrip meander line and parallel grating and isolated independent conductors for a uniform current distribution without variable coupling. The analysis, computer program and its use ... |
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| Dielectric Waveguide Circulator. |
13 OCT 1981 |
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| Authors:
Richard A. Stern; Richard W. Babbitt; DEPARTMENT OF THE ARMY WASHINGTON DC
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| Millimeter wave circulators are disclosed for use with millimeter wavelength dielectric waveguides. The structure comprises a prism of magnetized ferrimagnetic material with the waveguide ends bonded to the lateral faces of the prism. The waveguide ends and the lateral faces are congruent rectangles. The prisms may have triangular bases in which case a Y-junction circulator results, or square bases with waveguide ends attached to three out of four of the ... |
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| Magnetic Characteristics of Th(6-x)Y(x)Mn23 Hydrides |
17 AUG 1981 |
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| Authors:
E. B. Boltich; W. E. Wallace; F. Pourarian; S. K. Malik; PITTSBURGH UNIV PA DEPT OF CHEMISTRY
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| Analysis and Computer Studies for Magnetostatic Surface Wave Transducers |
MAY 1981 |
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| Authors:
Jacob I. Weinberg; LOWELL UNIV MA
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| This report summarizes results of work on magnetostatic surface wave transducers. Presented are the results for the dispersion relation, radiation resistance and insertion loss for magnetostatic surface wave transducers which may include a gap and apodization. Independent conductors as well as normal modes are considered. Also presented are the results for the dispersion relation for surface waves for a variety of alignments of the externally applied magnetic biasing field. Computerized ... |
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| Microwave Power Limiter Using Electrically Thin Iris. |
15 MAY 1979 |
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| Authors:
Harry Goldie; N. Stitzer; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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| A ferrimagnetic sphere that is biased to the subsidiary resonance mode and placed within a microwave slotted resonant structure functions as a frequency selective microwave power limiter. When the power level of a signal at the input port exceeds a threshold level, the device prevents the power level at the output port from increasing further. A weak signal present simultaneously passes with relatively little attenuation if it is slightly offset ... |
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| Local Site Distortion Model of Magnetostriction. |
29 NOV 1978 |
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| Authors:
Gerald F. Dionne; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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| A new model is proposed to explain the magnetostriction effects in ferrimagnetic spinels and garnets with Mn(3+), co(2+), and Fe(2+) ions substituted into octahedral sites. Considerable experimental evidence has revealed that small amounts of each of these ions will alter substantially the magnitude of either the lambda 100 or lambda 111 magnetostriction constant, depending on the particular ion. The theory is based on the concept that Jahn-Teller effects produce local ... |
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| Mossbauer and Magnetic Studies of a Mixed-Valence Ferrimagnet, Fe2F5.2H2O. |
06 MAY 1977 |
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| Authors:
E. G. Walton; D. B. Brown; H. Wong; W. M. Reiff; VERMONT UNIV BURLINGTON DEPT OF CHEMISTRY
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| The red, crystalline mixed-valence compound pentafluorodiiron(II,III)dihydrate, Fe2F5.2H2O, has been examined using Mossbauer spectroscopy and magnetic susceptibilities. At 48K the material orders ferrimagnetically as the result of spin compensation of iron (III) by iron(II). Above this critical temperature, the observation of distinct quadrupole-split Mossbauer absorptions for iron(II) and iron(III) sites demonstrates the non-equivalence of oxidation states and established Fe2F5.2H2O as a Class II mixed-valence compound. In the temperature range 49=300 K, ... |
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| Superconductors, Magnetic Detectors and Magnetic Electronics. |
10 NOV 1976 |
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| Authors:
M. Tinkham; HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS
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| This report covers work in opening up the far infrared to useful application in the study of solids: finding and studying the energy gap in superconductors, first observation of antiferromagnetic resonance and exchange resonances in the far infrared, first observation of the temperature-dependent soft mode in ferroelectric crystals, first observation of the far-infrared absorption due to random charge in disordered systems, the effect of magnetic fields in creating gapless superconductors ... |
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| Field-Induced Transitions in DySb, |
1974 |
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| Authors:
T. O. Brun; G. H. Lander; F. W. Korty; J. S. Kouvel; ILLINOIS UNIV AT CHICAGO CIRCLE
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| The field-induced transitions in a DySb crystal have been studied by neutron diffraction and magnetization measurements in fields up to approx. 60 kOe applied parallel to each of the principal axes. In the case, the transition from the A to an intermediate ferrimagnetic (Q) state is first-order at 4.2 K (critical field H(c) approx. equal 21 kOe) but is continuous from approx. 6 K up to T(N), as H(c) approaches ... |
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Reports by Keyword(s)
FERRIMAGNETISM
