US3110674A - Piezoelectric-ferromagnetic material - Google Patents
Piezoelectric-ferromagnetic material Download PDFInfo
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- US3110674A US3110674A US841699A US84169959A US3110674A US 3110674 A US3110674 A US 3110674A US 841699 A US841699 A US 841699A US 84169959 A US84169959 A US 84169959A US 3110674 A US3110674 A US 3110674A
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- Prior art keywords
- oxide
- gallium
- crystals
- iron
- degrees
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- 239000003302 ferromagnetic material Substances 0.000 title description 3
- 239000013078 crystal Substances 0.000 claims description 18
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 13
- 239000000155 melt Substances 0.000 claims description 8
- AJNVQOSZGJRYEI-UHFFFAOYSA-N digallium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Ga+3].[Ga+3] AJNVQOSZGJRYEI-UHFFFAOYSA-N 0.000 claims description 5
- 230000001747 exhibiting effect Effects 0.000 claims description 5
- JSUIEZRQVIVAMP-UHFFFAOYSA-N gallium iron Chemical compound [Fe].[Ga] JSUIEZRQVIVAMP-UHFFFAOYSA-N 0.000 claims description 5
- QZQVBEXLDFYHSR-UHFFFAOYSA-N gallium(III) oxide Inorganic materials O=[Ga]O[Ga]=O QZQVBEXLDFYHSR-UHFFFAOYSA-N 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 5
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(III) oxide Inorganic materials O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 claims description 4
- 229910052810 boron oxide Inorganic materials 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 239000002178 crystalline material Substances 0.000 claims description 3
- 230000005294 ferromagnetic effect Effects 0.000 claims description 3
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 claims 1
- MOWNZPNSYMGTMD-UHFFFAOYSA-N oxidoboron Chemical compound O=[B] MOWNZPNSYMGTMD-UHFFFAOYSA-N 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 13
- 229910052742 iron Inorganic materials 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 5
- 229910052733 gallium Inorganic materials 0.000 description 5
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 4
- 230000005291 magnetic effect Effects 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 3
- -1 gallium ions Chemical class 0.000 description 3
- 235000013980 iron oxide Nutrition 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 229910001195 gallium oxide Inorganic materials 0.000 description 2
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 2
- 238000003801 milling Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 235000015115 caffè latte Nutrition 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000005307 ferromagnetism Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
- H01F1/0311—Compounds
- H01F1/0313—Oxidic compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G7/00—Capacitors in which the capacitance is varied by non-mechanical means; Processes of their manufacture
- H01G7/02—Electrets, i.e. having a permanently-polarised dielectric
- H01G7/025—Electrets, i.e. having a permanently-polarised dielectric having an inorganic dielectric
Definitions
- This invention relates to a ferromagnetic material, more particularly to a ferromagnetic material which concurrently exhibits piezoelectric properties, and to its method of preparation.
- the novel material has the chemical formula where x has a value between .7 and 1.4 and can be described as a gallium-iron oxide. It is believed that this is the only material presently known exhibiting measurable amounts of piezoelectricity and ferromagnetism concurrently.
- Material of this kind is especially useful in various electrical devices, particularly in forms of transducers, electromechanical resonators and nonreciprocal devices.
- the material has been prepared both in ceramic and single crystal form and has exhibited the described properties in each form, although the properties are more pronounced in the single crystal form.
- Single crystals of the material can be grown by preparing a melt of gallium sesquioxide (Gri -O ferric oxide (Fe O boron oxide (B 0 and bismuth trioxide (Bi O the latter two components being found advantageous for serving as fluxes, and allowing the melt to cool at a controlled rate.
- the resulting gallium-iron oxide crystals can be extracted from the cooled solid mass by immersing the mass in a hot dilute aqueous solution of nitric acid.
- the ratio of gallium ions to iron ions in the grown crystal can be controlled by proportioning accordingly the relative amounts of Ga O and Fe O in the melt.
- the ceramic form can be prepared by milling together appropriate amounts of Ga O and F5203 with water for forming a slurry, pressing the resulting slurry into discs, firing the discs, and then allowing the discs to cool slowly.
- One specific example of the fabrication of the single crystal form is as follows. There were placed in a 100 cubic centimeter platinum crucible 6.5 grams each of gallium sesquioxide and ferric oxide, 4.0 grams of boron oxide, and 35 grams of bismuth trioxide. The crucible was covered and placed in an electric furnace, heated to 1125 degrees C. and kept at that temperature for five hours. The melt was thereafter cooled at the controlled rate of between four and seven degrees C. per hour until a temperature of about 500 degrees C. was reached, after which power to the furnace was turned off and the furnace allowed to cool rapidly at an uncontrolled rate since below this temperature the rate of cooling was found not to be important.
- the resulting crystals were extracted from the solidificd mass by immersion for several hours, typically four hours, in 15 percent aqueous solution of nitric acid heated to degrees C.
- the crystals recovered were found to exhibit magnetic Curie points varying from slightly above room temperature to considerably below room temperature. However, all the crystals were piezoelectric from room temperature to the temperature of liquid nitrogen, 77 degrees K., exhibiting piezoelectricity to about the same extent as quartz.
- the crystals found by chemical analysis to have substantially equimolar proportions of gallium and iron had magnetic Curie points of about 260 degrees K.
- the magnetic Curie point was found to be dependent on the iron content, increasing with increasing iron content.
- the magnetic Curie point was found to be above room temperature for crystals in which the iron concentration by number of atoms was at least about 60 percent of the total iron-gallium content, corresponding to a value of x in the formula set forth above in the range between 1.2 and 1.4.
- the stoichiometric form GaFeO at room temperature had a conductivity of 2 1 0 'ohm-centimeters indicating that the material is an insulator.
- single crystals were grown from a melt formed by adding together in a suitable crucible 12.5 grams of Ga O 10.6 grams of Fego 14.0 grams of B 0 and 60 grams of Bi O This melt was held at 1100 degrees C. for two hours and then cooled at the rate of about 7.0 degrees C. per hour to 600 degrees C. and the crucible was thereafter air-quenched for cooling.
- the amounts used of the B 0 and Bi O fluxes should be adequate to insure complete dissolution of the gallium and iron oxides.
- the use of extra gallium and iron oxides will simply result in a residue of the excess oxide in the solidified mass.
- the melting conditions are not critical. The temperature obviously must be sufficiently hi h to achieve adequate melting and mixing. However, it is found advantageous to avoid temperatures much in excess of 1200 degrees C. so as to remain in the equilibrium range for the desired compound. Under the conditions described, the crystals grown typically are about a centimeter long and several millimeters on a side in cross section.
- Ceramic compositions were prepared by adding appropriate amounts of gallium sesquioxide and ferric oxide into a polyethylene jar, adding one-half inch diameter porcelain balls and distilled water, and milling the mixture for sixteen hours. The relative amounts of the two oxides used were chosen to provide a desired ratio in the gallium and iron content of the ceramic. The slurry was then filtered, dried and sieved. Discs of about one centimeter diameter and one millimeter thick were pressed together under five tons of pressure on a three and one-half inch ram. The discs were then placed on a platinum sheet and into an electric furnace which was then heated to 1400 degrees C. and held at that temperature for seven hours. The discs were then allowed to cool at a gradual uncontrolled rate. Of course, the various parameters of this process can be varied over wide limits without too significant a change in the end product.
- Crystalline material having an orthorhombic struc ture and exhibiting both ferromagnetic and piezoelectric properties having the chemical formula Ga Fe O where x has a value between .7 and 1.4.
- Crystalline material having an orthorhombic structure and exhibiting both ferromagnetic and piezoelectric properties having the chemical formula Ga Fe Where x has a vaiue bewveen 1.2 and 1.4.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Description
United States Patent 3,110,674 PIEZOELECTRIC-FERRGMAGNETIC MATERIAL Joseph P. Remeika, Berkeley Heights, NJ., assignor to Bell Telephone Laboratories, Incorporated, New York,
N.Y., a corporation of New York No Drawing. Filed Sept. 23, 1959, Ser. No. 841,699 3 Claims. (Cl. 252-62.5)
This invention relates to a ferromagnetic material, more particularly to a ferromagnetic material which concurrently exhibits piezoelectric properties, and to its method of preparation.
The novel material has the chemical formula where x has a value between .7 and 1.4 and can be described as a gallium-iron oxide. It is believed that this is the only material presently known exhibiting measurable amounts of piezoelectricity and ferromagnetism concurrently.
Material of this kind is especially useful in various electrical devices, particularly in forms of transducers, electromechanical resonators and nonreciprocal devices.
The material has been prepared both in ceramic and single crystal form and has exhibited the described properties in each form, although the properties are more pronounced in the single crystal form.
Single crystals of the material can be grown by preparing a melt of gallium sesquioxide (Gri -O ferric oxide (Fe O boron oxide (B 0 and bismuth trioxide (Bi O the latter two components being found advantageous for serving as fluxes, and allowing the melt to cool at a controlled rate. The resulting gallium-iron oxide crystals can be extracted from the cooled solid mass by immersing the mass in a hot dilute aqueous solution of nitric acid. The ratio of gallium ions to iron ions in the grown crystal can be controlled by proportioning accordingly the relative amounts of Ga O and Fe O in the melt.
The ceramic form can be prepared by milling together appropriate amounts of Ga O and F5203 with water for forming a slurry, pressing the resulting slurry into discs, firing the discs, and then allowing the discs to cool slowly.
In each form, X-ray powder diffraction photographs have shown that a single phase of the orthorhombic crystal structure persists between Ga Fe O and with a regular change in lattice constant. Beyond these limits, free ferric oxide is found in the iron-rich specimen and free gallium sesquioxide in the gallium-rich end.
One specific example of the fabrication of the single crystal form is as follows. There were placed in a 100 cubic centimeter platinum crucible 6.5 grams each of gallium sesquioxide and ferric oxide, 4.0 grams of boron oxide, and 35 grams of bismuth trioxide. The crucible was covered and placed in an electric furnace, heated to 1125 degrees C. and kept at that temperature for five hours. The melt was thereafter cooled at the controlled rate of between four and seven degrees C. per hour until a temperature of about 500 degrees C. was reached, after which power to the furnace was turned off and the furnace allowed to cool rapidly at an uncontrolled rate since below this temperature the rate of cooling was found not to be important.
The resulting crystals were extracted from the solidificd mass by immersion for several hours, typically four hours, in 15 percent aqueous solution of nitric acid heated to degrees C.
The crystals recovered were found to exhibit magnetic Curie points varying from slightly above room temperature to considerably below room temperature. However, all the crystals were piezoelectric from room temperature to the temperature of liquid nitrogen, 77 degrees K., exhibiting piezoelectricity to about the same extent as quartz. The crystals found by chemical analysis to have substantially equimolar proportions of gallium and iron had magnetic Curie points of about 260 degrees K. The magnetic Curie point was found to be dependent on the iron content, increasing with increasing iron content. The magnetic Curie point was found to be above room temperature for crystals in which the iron concentration by number of atoms was at least about 60 percent of the total iron-gallium content, corresponding to a value of x in the formula set forth above in the range between 1.2 and 1.4.
The stoichiometric form GaFeO at room temperature had a conductivity of 2 1 0 'ohm-centimeters indicating that the material is an insulator.
As another example, single crystals were grown from a melt formed by adding together in a suitable crucible 12.5 grams of Ga O 10.6 grams of Fego 14.0 grams of B 0 and 60 grams of Bi O This melt was held at 1100 degrees C. for two hours and then cooled at the rate of about 7.0 degrees C. per hour to 600 degrees C. and the crucible was thereafter air-quenched for cooling.
In such processes the amounts used of the B 0 and Bi O fluxes should be adequate to insure complete dissolution of the gallium and iron oxides. The use of extra gallium and iron oxides will simply result in a residue of the excess oxide in the solidified mass. The melting conditions are not critical. The temperature obviously must be sufficiently hi h to achieve adequate melting and mixing. However, it is found advantageous to avoid temperatures much in excess of 1200 degrees C. so as to remain in the equilibrium range for the desired compound. Under the conditions described, the crystals grown typically are about a centimeter long and several millimeters on a side in cross section.
Ceramic compositions were prepared by adding appropriate amounts of gallium sesquioxide and ferric oxide into a polyethylene jar, adding one-half inch diameter porcelain balls and distilled water, and milling the mixture for sixteen hours. The relative amounts of the two oxides used were chosen to provide a desired ratio in the gallium and iron content of the ceramic. The slurry was then filtered, dried and sieved. Discs of about one centimeter diameter and one millimeter thick were pressed together under five tons of pressure on a three and one-half inch ram. The discs were then placed on a platinum sheet and into an electric furnace which was then heated to 1400 degrees C. and held at that temperature for seven hours. The discs were then allowed to cool at a gradual uncontrolled rate. Of course, the various parameters of this process can be varied over wide limits without too significant a change in the end product.
What is claimed is:
1. Crystalline material having an orthorhombic struc ture and exhibiting both ferromagnetic and piezoelectric properties having the chemical formula Ga Fe O where x has a value between .7 and 1.4.
2. Crystalline material having an orthorhombic structure and exhibiting both ferromagnetic and piezoelectric properties having the chemical formula Ga Fe Where x has a vaiue bewveen 1.2 and 1.4.
3. The process of n'eparing single crystals of galliumiron oxide comprising the steps of melting together gallinm sesquioxidc, ferric oxide, boron oxide and bismuth trioxide, cooling the melt slowly, and recovering gallium iron oxide crystals from the solidified mass.
References Cited in the file of this patent UNITED STATES PATENTS 2,657,122 Chaudoye et a1. Get. 27, 1953 2,657,458 Pessel Nov. 3, 1953 2,691,738 Matthias Oct. 12, 1954 2,715,109 Abel's-Schoenberg Aug. 9, 1955 2,721,182 Clement Oct. 18, 1955 2,848,310 Rerneika Aug. 19, 1958 2 849,404 latte et a1. Aug. 26, 1958 2,852,420 Pohl Sept. 16, 1958 2,872,299 Celiner et al Feb. 3, 1959 2,892,739 Rusler June 30, 1959 2,957,827 Nielsen Oct. 25, 1960 3,053,770 Counts -2 Sept. 11, 1962 OTHER REFERENCES Lcnsen et 211.: Comptes Rcnclus, vol. 236, pp. 1997-8, March 31, 1958.
Pautrhenet: J. Applied lllysics, April 1959, pp. 29OS 2925.
Anderson: 1. Applied Physics, April 1959, p. 2998, Div. 64.
Claims (2)
1. CRYSTALLINE MATERIAL HAVING AN ORTHORHOMBIC STRUCTURE AND EXHIBITING BOTH FERROMAGNETIC AND PIEZOELECTRIC PROPERTIES HAVING THE CHEMICAL FORMULA GA2-XFEXO3 WHERE X HAS A VALUE BETWEEN .7 AND 1.4.
3. THE PROCESS OF PREPARING SINGLE CRYSTALS OF GALLIUMIRON OXIDE COMPRISING THE STEPS OF MELTING TOGETHER GALLIUM SESQUIOXIDE, FERRIC OXIDE, BORON OXIDE AND BISMUTH TRIOXIDE, COOLING THE MELT SLOWLY, AND RECOVERING GAL/ LIUM IRON OXIDE CRYSTALS FROM THE SOLIDIFIED MASS.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US841699A US3110674A (en) | 1959-09-23 | 1959-09-23 | Piezoelectric-ferromagnetic material |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US841699A US3110674A (en) | 1959-09-23 | 1959-09-23 | Piezoelectric-ferromagnetic material |
Publications (1)
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US3110674A true US3110674A (en) | 1963-11-12 |
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US841699A Expired - Lifetime US3110674A (en) | 1959-09-23 | 1959-09-23 | Piezoelectric-ferromagnetic material |
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Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2442982A (en) * | 1946-03-19 | 1948-06-08 | Atlantic Refining Co | Desulfurization of hydrocarbons |
US2509654A (en) * | 1947-08-14 | 1950-05-30 | Lincoln Electric Co | Fluxes for use in arc welding |
US2657221A (en) * | 1949-07-21 | 1953-10-27 | Ciba Ltd | Vat dyestuff |
US2657458A (en) * | 1949-01-29 | 1953-11-03 | Rca Corp | Method of joining copper members |
US2691738A (en) * | 1949-04-08 | 1954-10-12 | Bell Telephone Labor Inc | Electrical device embodying ferroelectric lanthanum-containing substances |
US2715109A (en) * | 1954-06-14 | 1955-08-09 | Steatite Res Corp | Ferromagnetic ceramic materials with hysteresis loops of rectangular shape |
US2721182A (en) * | 1953-09-21 | 1955-10-18 | Csf | New piezo-electric ceramic material and process for making it |
US2848310A (en) * | 1954-12-14 | 1958-08-19 | Bell Telephone Labor Inc | Method of making single crystal ferrites |
US2849404A (en) * | 1956-04-13 | 1958-08-26 | Jaffe Bernard | Morphotropic piezoelectric ceramics |
US2852420A (en) * | 1956-06-28 | 1958-09-16 | Rauland Corp | Method of manufacturing semiconductor crystals |
US2872299A (en) * | 1954-11-30 | 1959-02-03 | Rca Corp | Preparation of reactive materials in a molten non-reactive lined crucible |
US2892739A (en) * | 1954-10-01 | 1959-06-30 | Honeywell Regulator Co | Crystal growing procedure |
US2957827A (en) * | 1957-04-30 | 1960-10-25 | Bell Telephone Labor Inc | Method of making single crystal garnets |
US3053770A (en) * | 1958-04-17 | 1962-09-11 | Gen Motors Corp | Permanent magnet |
-
1959
- 1959-09-23 US US841699A patent/US3110674A/en not_active Expired - Lifetime
Patent Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2442982A (en) * | 1946-03-19 | 1948-06-08 | Atlantic Refining Co | Desulfurization of hydrocarbons |
US2509654A (en) * | 1947-08-14 | 1950-05-30 | Lincoln Electric Co | Fluxes for use in arc welding |
US2657458A (en) * | 1949-01-29 | 1953-11-03 | Rca Corp | Method of joining copper members |
US2691738A (en) * | 1949-04-08 | 1954-10-12 | Bell Telephone Labor Inc | Electrical device embodying ferroelectric lanthanum-containing substances |
US2657221A (en) * | 1949-07-21 | 1953-10-27 | Ciba Ltd | Vat dyestuff |
US2721182A (en) * | 1953-09-21 | 1955-10-18 | Csf | New piezo-electric ceramic material and process for making it |
US2715109A (en) * | 1954-06-14 | 1955-08-09 | Steatite Res Corp | Ferromagnetic ceramic materials with hysteresis loops of rectangular shape |
US2892739A (en) * | 1954-10-01 | 1959-06-30 | Honeywell Regulator Co | Crystal growing procedure |
US2872299A (en) * | 1954-11-30 | 1959-02-03 | Rca Corp | Preparation of reactive materials in a molten non-reactive lined crucible |
US2848310A (en) * | 1954-12-14 | 1958-08-19 | Bell Telephone Labor Inc | Method of making single crystal ferrites |
US2849404A (en) * | 1956-04-13 | 1958-08-26 | Jaffe Bernard | Morphotropic piezoelectric ceramics |
US2852420A (en) * | 1956-06-28 | 1958-09-16 | Rauland Corp | Method of manufacturing semiconductor crystals |
US2957827A (en) * | 1957-04-30 | 1960-10-25 | Bell Telephone Labor Inc | Method of making single crystal garnets |
US3053770A (en) * | 1958-04-17 | 1962-09-11 | Gen Motors Corp | Permanent magnet |
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