US3031405A - Ferromagnetic materials having a rectangular hysteresis cycle - Google Patents

Ferromagnetic materials having a rectangular hysteresis cycle Download PDF

Info

Publication number
US3031405A
US3031405A US701612A US70161257A US3031405A US 3031405 A US3031405 A US 3031405A US 701612 A US701612 A US 701612A US 70161257 A US70161257 A US 70161257A US 3031405 A US3031405 A US 3031405A
Authority
US
United States
Prior art keywords
core
cycle
variation
molecular
magnetic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US701612A
Other languages
English (en)
Inventor
Pierrot Andre
Lescroel Yves
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lignes Telegraphiques et Telephoniques LTT SA
Original Assignee
Lignes Telegraphiques et Telephoniques LTT SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lignes Telegraphiques et Telephoniques LTT SA filed Critical Lignes Telegraphiques et Telephoniques LTT SA
Application granted granted Critical
Publication of US3031405A publication Critical patent/US3031405A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/34—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites
    • H01F1/342—Oxides
    • H01F1/344—Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
    • C04B35/265—Compositions containing one or more ferrites of the group comprising manganese or zinc and one or more ferrites of the group comprising nickel, copper or cobalt

Definitions

  • AVAVAVAVAVAYAZAVAVAVAVA Numana@tnvAvAvAvAvA AVAVAVMQVAVM
  • VVAVAVAVAVA AvAvAvAvgAvAvAzAvV/f/ muuu AVAVAVVNAVNAVA@avAvAvmvAvA mwunnmvmwAvAvAvAnyAvA mmvAvAvAvAvAvAv);vAvAvAvAvAnzv mi vvznvvvvvvvvvvv Attorney April 24, 1962 A.
  • the present invention relates to ferromagnetic materials of the ferrite type, having substantially rectangular hysteresis cycles and methods of manufacturing such materials. Materials of this kind can be employed in magnetic recording devices known as memory devices, magnetic control members, magnetic amplifiers, etc. In such applications these materials are used in the form of cores, usually of toroidal shape or at least of closed shape, without air-gap.
  • Rm % or ratio of reetangularity
  • the permeability a is defined as the initial permeability in the demagnetised state.
  • Ri 800 2 F- (T) Rp being the loss resistance, expressed in ohms
  • f being the frequency, expressed in cycles per second
  • L being the inductance, expressed in henrys.
  • the Curie point 0c in the following will be, by convention, the temperature expressed in degrees centigrade, above which the material is no longer' ferromagnetic.l
  • the magnetostrictive effects can be characterised by the value of the coefficient of magnetostriction at saturation xs, obtained by extrapolating for the demagnetised state the relative curve of variation inthe direction of the applied field, of the length l of the Y by a coefficient of variation of induction in percent per degree:
  • the induction B1,r1 corresponds to a particular field Hm which is clearly higher than Hc.
  • the response time is defined by considering two windings with negligible time constants placed on a core made of the magnetic material concerned, this core is 3 l subjected to the magnetising field Hm comprised between H,m and ZHcm, then to the field Anegative impulse I; two positive impulses value l/2; a negative impulse of- I.v
  • the interval between the pulses is 50 microseconds, the rise time of each impulse being 0.3 microsecond.
  • v ⁇ The response given in winding N2 to the second impulse is then considered.
  • the response timeV 1- is taken as the time, in microseconds, required forthe voltage produced in winding N2, starting from one tenth of the maximum to pass through the maximum andY return to of the value of this maximum.
  • the object of the invention is to produce magnetic materials of the ferrite type having on the one hand, substantially rectangular hysteresis cycles, and on the other hand high resistivities p at leastequal to 103 ohms-centi# metre.
  • the -rectangularity of the cycle is obtained by starting ⁇ y
  • a cycle of rectangularity having a coeiicient of rectangularity m at least equal to 0.8 may be obtained.
  • magnetic materials o f the above kind in addition to the natural stresses obtained during heat treatment may be subjected in the form of the finished core to external artificial mechanical stresses. It has been vertiiied that in this way the rec tangularity of the cycle is further improved; a coefficient of rectangularity ,8m atleast equal to 0.95 is obtained, and, what is particularly remarkable, a rectangularity ratio Rm greater than 0.9 is obtained, a value unequalled hitherto. j
  • the said external artificial mechanical stresses can be realised by known'p'rocesses, hydraulic, the core being placed in a receptacle into which oil or water is forced under pressure, or mechanical,
  • the ferromagnetic materials which are the object of the present invention are ferromagnetic materials of the ferrite type, with substantially rectangular hysteresis cycle, manufactured by compressing a homogeneous mixture of fine powders of metallic oxides under a pressure of from 0.5 to l5 tons per square centimetre and by sub-V jecting the cores obtained from the mixture to a heat treatment consisting of heating to a temperature coma prised between 900 C. to 1,300 C. in oxygen, followed if by cooling for about l5 hours, the said mixture consiste.”
  • ferrie oxide and optionally oxides of trivalent 4 metals ofthe group comprising aluminum and chromium, oxides of at least two bivalent metals of the group containing nickel and copper, and optionally oxides of bivalent metals of the group comprising zinc and cadmium,
  • the sum of 'i the molecular percentages of the oxides of the trivalent metals is comprised between 47 and 50, the sum of the molecular percentages of the oxides of the trivalent metals, other than iron, being less than or equal to 2, the sum of the molecular percentages, of the oxides of the bivalent metals of the group comprising nickel and copper being comprised between ⁇ 25 and 53; kthe percentage of the copper oxide being comprised bef tween 3 and 15 and the sum of the molecular percentages of the oxides of bivalentmetals ⁇ of the group ⁇ comprising zinc and cadmium being .at most equal to 25. i
  • This artificial mechanical stress is applied to the core after heat treatment and the applied stress is maintained during use.
  • these materials haveV negligible eddy-current losses which enable them to be used at high frequency with low response time (flO microseconds).
  • the materials in accordance with the invention have coliicients of rectangularity m abd ratios of rectangularity at least equal .to the values indicated above.
  • Y they have inductions at saturation (s) ofthe order of 1,500 to 4,500 gausses ⁇ at ⁇ 20 C. coefficients of variation the given percentages of Fe203 after grinding must be increased by this quantity; it wouldbe necessary to make corrections if a mill were used which wore out more slowly or more quickly.
  • FIG. 1 represents a substantially rectangular hysteresis i cycle:
  • FIG. 3 represents curves of variation of induction Bm, as a function of the molecular percentage of Fe203
  • FIG. 4 represents curves of variation of the coefficient of rectangularity m as a function of the molecular percentage of Fe203
  • FIG. 5 represents curves of variation of induction Bm, as a function of the molecular percentage of A1203 or of C1203 in a defined compound
  • FIG. 6 represents curves of variation of the coefficient of rectangularity 18m as a function of molecular percentage of A1203 or Cr203, in a defined compound.
  • FIG. 7 represents the variation of the induction Bm as a function of Hm for a defined compound
  • FIG. 8 represents the variation of Rm, and of ,Bm as a function of H,nn for a defined compound
  • FIG. 9 represents the variation of the induction Bm as a function of the temperature for two defined compounds.
  • FIG. 10 represents the variations of the coercive eld Hem, as a function of the temperature for two defined compounds
  • FIG. l1 represents the Variation of the ratio of rectangularity m, as a function of the temperature for two defined compounds
  • FIGS. 12 to 16 represent hysteresis cycles of material according to the invention.
  • FIGS. 17, 17a and 18, 18a each represent, in horizontal and Vertical section a core enveloped in a polyester resin
  • FIG. 19 represents, for different fields, hysteresis cycles for a magnetic core not enveloped and for the same core enveloped in polyester resin.
  • FIG. 2 represents a triangular diagram corresponding to a material according to the invention, of which the three components are: the sum of the molecular percentages of the oxides of trivalent metals Fe203, Cr203, A1203, the sum of the molecular percentages of the oxides of bivalent metals NiO and CuO and the sum of the molecular ⁇ percentages of bivalent metals ZnO and CdO.
  • the figurative point of the composition with rectangular hysteresis cycle, in accordance with the invention, must be located inside the hatched zone A, ⁇ B, C, D, which appears in the formof an elongated parallelogram. Above the limit C -B there may again be compositions satisfying ⁇ the condition lof rectangularity mOO but the Curie point 6., becomes lower as the molecular content of Zn0 increases and the condition oB 0.50 can no longer be guaranteed.
  • the molecular percentage of Cu0 wasaS, and each curve corresponds to a family of compounds of constant molecular content of Zn0; these molecular percentages of ZnO corresponding to the four curves are respectively 0, 5, l0 and 15. All these compounds have been treated under the same conditions; in particular they have been sintered at 1200 C. for two hours in oxygen. It will be noted that when the molecular percentage of Z110 increases, the maximum of Bm is shifted to the right, that is to say, towards higher molecular percentages of Fe202 and that this maximum reaches a higher value.
  • FIG. 5 shows the variation of the induction Bm, marked at 10 oersteds, for a family of compounds:
  • l49Fe203, 36Ni0, 5CuO, lOZnO has the effect of reducing the maximum induction.
  • FIG. 6 is represented the variation of the coefiicient of rectangularity ,6m marked at l0 oersteds, for the same family of compounds as that corresponding to FIG. 5, as a function of the molecular percentage of A1203 (curve C3) or as a function of the molecular percentage of Cr203 (curve C4). All these compounds have been treated under the same conditions and in particular have been sintered at 1,200 C. for two hours in oxygen. The coefificient for rectangularity m decreases slightly when the molecular content of Cr203 or of A1203 increases. It will be seen moreover, that in both cases ⁇ the influence of Cr203 is more marked than that of A1203.
  • FIG. 7 represents the curve of variation of the induction Bm, as a function of the field Hm; it is in fact the curve of first magnetisation.
  • FIG. 10 represents the variation of the coercive eld Hen, for a cycle marked at Hm-f-lO-oersteds between -40 C. and +100" C.; in considering the range from' 20 C. to 80 C., it ⁇ is possible to deduce therefrom:
  • the atmosphere of annealing will be pure oxygen.
  • FIGS. 12, 13, 14, 15 and 116 ⁇ represent the. ⁇ hysteresis i cycles, plotted in direct current, for a maximum eld of 10 oersteds and for another ⁇ smaller iield if necessary.' In the latter case, the figure comprises two cycles, that 1 plotted for a eld lower than 10 oersteds being inside the 1 other.
  • the annealing is carried out at 1,200 C. for 2 hours in oxygen.
  • FIG. 1,1 represents the variation of the coefficient of Table I- 1 v i 'TABLE I Molecular Composition in percent Magnetic Characteristics Y Fig. Nos. Y
  • 11 11 1 11 1 1 s is s 1111 13 49 0 36 5 1 ⁇ 3.4 2:2140 22 0.?05 "'i s0 41000 0-2 11 -1 11 1 11 1 11 11 at a as .1.3 as 1111 0 15 49 0 31 5 15 i 3 2,770 1.3 Y 0.90 150 5,000 0102 16 475 0 32.5 15 5 1o 2,630 2.0 0.87 s0 5,000 ⁇ 1.0
  • Magnetic materials having theV compositions indicated above and subjected to the grinding', pressing and heat treatment described, are then subjected to stresses by one ofthe known methods given in a non-limitative Vmanner, previously.
  • stresses by one ofthe known methods given in a non-limitative Vmanner, previously.
  • a thermosetting resin which permits a considerable shrinkage (10 to 15% after polymerisation) and does not split.
  • a cobalt accelerator in principle: cobalt naph thenate or octoate dissolved in a solventsuch as those" commercially known as white spirit or styrolene.
  • Ratio of proportions u s g 1 50 Resin Catalyst g-- p 5 Accelerator drops.. 2
  • the grinding is carried out for 48 hour-s with an iron i plained hereinafter for the particular case of coating of the magnetic material by polyester resin.
  • FIGURE 17 shows a core of magnetic material 1 comf pletely coated in polyester resin 2, in which a hole 3 which T is chosen from the group consisting of aluminum and chromium with the values expressed in molecular percentages, x-i-y is between 47 and 50, y is between 0 and 2, v is between 3 and 15, u-I-v is between 35 and 53 has been arranged to avoid the splitting of the resin in 5 and s is between 0 and 15, x, y, u, v and s being equal to shrinkage.
  • FIGURE 18 represents the same core 1 ex- 100, pressing said mixture into core form at a pressure ternally banded by polyester resin 4.
  • sultermg hours at 1,200 C., in which T is chosen from the group consisting of alumill OXYgeD- h num and chromium, x-l-y is between 47 and 50, y is ⁇ be- In the whole of the followmg, the characterrstlcs of the 2O tween 0 and 2, v is between 3 and 15 +V is between 35 hystresls cycle have be@ maled on.
  • the cycles a, b and c correspond to the uncoated core Sald core' antd cyclfs d e g and h t0 the com coated Wlth Poly' 30 References Cited in the le of this patent es er resin.
  • Aug. 28, 1951 given is comprised between 1.0 and 1.5 ms. 2,579,267 Leverenz et al. Dec. 18, 1951 2,601,212 Polydoroif June 12, 1952 Values of the respectlve lntensitles. 2,685,568 Wilson Aug. 3 1954 Complete pulses ma 500 2,723,239 Harvey Nov. 8, 1955 Partial pulses ma 250 2,744,873 Piekarski May 8, 1956 For an uncoated Core: Bruner May 29, Useful signal (response given by the core after the 2849312 Pfterman Aug 26 1958 Second pulse), mv f 55 2,962,445 Plerrot et al. Nov. 29, 1960 1 nterlfegeng signal (response given by the core after the FOREIGN PATENTS as pu se mv.
  • Ratio useful signal/interference signal 2.1. great infin? Aug- 17 1955 Response time; between 1 and 1.5 ms. 752659 Gigi E obciza coated core, according to FIGURE 17 or 18, we 60 1:10,]:654 France Aug. 10; 1955 Useful signal, mv 1,122,258 France May 22, 1956 ISligtnal intrierencf/"gnh 3 5 OTHER REFERENCES a 1o use u -s1 n 1n e erence, Response time? between 1 and 1.5 las. for the same 65 Gorter: Phihps Research Reports, vol. 9, No. 6, p. 432, relative values of current intensity.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Power Engineering (AREA)
  • Soft Magnetic Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Magnetic Ceramics (AREA)
US701612A 1956-12-14 1957-12-09 Ferromagnetic materials having a rectangular hysteresis cycle Expired - Lifetime US3031405A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR727692 1956-12-14
FR747548 1957-09-18

Publications (1)

Publication Number Publication Date
US3031405A true US3031405A (en) 1962-04-24

Family

ID=26183073

Family Applications (1)

Application Number Title Priority Date Filing Date
US701612A Expired - Lifetime US3031405A (en) 1956-12-14 1957-12-09 Ferromagnetic materials having a rectangular hysteresis cycle

Country Status (7)

Country Link
US (1) US3031405A (xx)
BE (1) BE562891A (xx)
CH (1) CH377539A (xx)
DE (1) DE1087507B (xx)
FR (2) FR1163304A (xx)
GB (1) GB828756A (xx)
NL (1) NL112299C (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3150095A (en) * 1961-11-24 1964-09-22 Ibm Ferrite ceramic compositions and method of preparation
EP1571688A1 (en) * 2004-03-05 2005-09-07 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus
US20050206329A1 (en) * 2004-03-16 2005-09-22 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1646997B1 (de) * 1965-08-10 1972-06-29 Siemens Ag Verfahren zur herstellung eines ferromagnetichen schaltkerns aus ferrit mit rechteckfoermiger hystereseschleife

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532876A (en) * 1946-12-19 1950-12-05 Asche Robert Electromagnetic artificial muscle
US2551711A (en) * 1943-07-01 1951-05-08 Hartford Nat Bank & Trust Co Manganese zinc ferrite core
US2565861A (en) * 1947-09-26 1951-08-28 Rca Corp Magnetic materials
US2579267A (en) * 1947-12-31 1951-12-18 Rca Corp Material having improved magnetic property
US2601212A (en) * 1948-11-09 1952-06-17 Gen Aniline & Film Corp Heat resistant magnetic cores and method of making
US2685568A (en) * 1950-05-10 1954-08-03 Gen Electric Soft ferromagnetic mixed ferrite material
GB735375A (en) * 1952-02-07 1955-08-17 Steatite Res Corp Ferromagnetic ceramic materials with hysteresis loops of rectangular shape
US2723239A (en) * 1952-09-29 1955-11-08 Rca Corp Ferrospinel compositions
FR1107654A (fr) * 1954-06-23 1956-01-04 Telecommunications Sa Matériaux ferrocéramiques magnétiques à pertes faibles
GB748070A (en) * 1953-12-21 1956-04-18 Philips Electrical Ind Ltd Improvements in or relating to methods of manufacturing ferromagnetic cores having substantially rectangular hysteresis loops
US2744873A (en) * 1952-11-08 1956-05-08 Gen Electric Mixed nickel, zinc, vanadium ferrite
US2748099A (en) * 1952-09-04 1956-05-29 Du Pont Polyamide compositions containing a high percentage of metal filler
GB752659A (en) * 1953-11-06 1956-07-11 Acec Improvements in and relating to ferrite compositions
FR1122258A (fr) * 1955-02-03 1956-09-04 Centre Nat Rech Scient Matériau ferromagnétique et son procédé de fabrication
US2849312A (en) * 1954-02-01 1958-08-26 Milton J Peterman Method of aligning magnetic particles in a non-magnetic matrix
US2962445A (en) * 1955-07-01 1960-11-29 Lignes Telegraph Telephon Rectangular hysteresis loop ferrites

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1058390A (fr) * 1951-07-24 1954-03-16 Steatite Res Corp Noyau ferromagnétique à coquilles, à perméabilité variable
BE523180A (xx) * 1952-10-02

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2551711A (en) * 1943-07-01 1951-05-08 Hartford Nat Bank & Trust Co Manganese zinc ferrite core
US2532876A (en) * 1946-12-19 1950-12-05 Asche Robert Electromagnetic artificial muscle
US2565861A (en) * 1947-09-26 1951-08-28 Rca Corp Magnetic materials
US2579267A (en) * 1947-12-31 1951-12-18 Rca Corp Material having improved magnetic property
US2601212A (en) * 1948-11-09 1952-06-17 Gen Aniline & Film Corp Heat resistant magnetic cores and method of making
US2685568A (en) * 1950-05-10 1954-08-03 Gen Electric Soft ferromagnetic mixed ferrite material
GB735375A (en) * 1952-02-07 1955-08-17 Steatite Res Corp Ferromagnetic ceramic materials with hysteresis loops of rectangular shape
US2748099A (en) * 1952-09-04 1956-05-29 Du Pont Polyamide compositions containing a high percentage of metal filler
US2723239A (en) * 1952-09-29 1955-11-08 Rca Corp Ferrospinel compositions
US2744873A (en) * 1952-11-08 1956-05-08 Gen Electric Mixed nickel, zinc, vanadium ferrite
GB752659A (en) * 1953-11-06 1956-07-11 Acec Improvements in and relating to ferrite compositions
GB748070A (en) * 1953-12-21 1956-04-18 Philips Electrical Ind Ltd Improvements in or relating to methods of manufacturing ferromagnetic cores having substantially rectangular hysteresis loops
US2849312A (en) * 1954-02-01 1958-08-26 Milton J Peterman Method of aligning magnetic particles in a non-magnetic matrix
FR1107654A (fr) * 1954-06-23 1956-01-04 Telecommunications Sa Matériaux ferrocéramiques magnétiques à pertes faibles
FR1122258A (fr) * 1955-02-03 1956-09-04 Centre Nat Rech Scient Matériau ferromagnétique et son procédé de fabrication
US2962445A (en) * 1955-07-01 1960-11-29 Lignes Telegraph Telephon Rectangular hysteresis loop ferrites

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3150095A (en) * 1961-11-24 1964-09-22 Ibm Ferrite ceramic compositions and method of preparation
EP1571688A1 (en) * 2004-03-05 2005-09-07 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus
US20050200263A1 (en) * 2004-03-05 2005-09-15 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus
US7385341B2 (en) 2004-03-05 2008-06-10 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus with magnetic spacers between magnetic rings
US20050206329A1 (en) * 2004-03-16 2005-09-22 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus
US7126292B2 (en) 2004-03-16 2006-10-24 Matsushita Toshiba Picture Display Co., Ltd. Cathode-ray tube apparatus

Also Published As

Publication number Publication date
CH377539A (fr) 1964-05-15
DE1087507B (de) 1960-08-18
BE562891A (xx)
NL112299C (nl) 1966-01-17
FR1163304A (fr) 1958-09-24
GB828756A (en) 1960-02-24
FR72272E (fr) 1960-03-31

Similar Documents

Publication Publication Date Title
US2723239A (en) Ferrospinel compositions
US2452529A (en) Magnet core
US2962445A (en) Rectangular hysteresis loop ferrites
DE973822C (de) Magnetkern und Verfahren zu seiner Herstellung
US3031405A (en) Ferromagnetic materials having a rectangular hysteresis cycle
US2685568A (en) Soft ferromagnetic mixed ferrite material
US3055833A (en) Mixed ferrospinels
DE907995C (de) Ferromagnetisches, hauptsaechlich aus Eisenoxydverbindungen vom Magnetit-Typ bestehendes keramisches Material und seine Herstellung
DE1227820B (de) Verfahren zur Herstellung von ferromagnetischen oxydischen Koerpern
US2961407A (en) Mixed ferrite composition
US3415751A (en) Manganese-zinc ferrites
US3372123A (en) Method for manufacturing lithiumnickel-manganese ferrite magnetic memory cores
AT164420B (de) Magnetischer Kern aus einem ferromagnetischen Ferrit
CH333347A (de) Verfahren zur Herstellung eines Magnetkernes mit einer nahezu rechteckigen Hystereseschleife
US2970112A (en) Ferromagnetic materials with rectangular hysteresis cycle and method for their manufacture
GB820853A (en) Improvements in or relating to methods of manufacturing non-metallic ferromagnetic materials
US3450635A (en) Nickel ferrites containing cobalt,lead and silicon
US3032503A (en) Composition of magnetic core material and method of producing same
USRE20507E (en) Magnetic material
DE1006090B (de) Verfahren zur Herstellung eines Ferrit-Werkstoffes fuer Magnetkerne, die eine nahezu echteckfoermige Hystereseschleife aufweisen
US3514405A (en) Ferromagnetic switching core of ferrite with rectangular hysteresis loop and process for the production thereof
US3188290A (en) Method of manufacturing a magnet core for use as a memory element
US2987481A (en) Manganese-zinc ferrite
Albers‐Schoenberg Ferrites
US3527706A (en) Method of manufacturing binder-containing permanent magnets on a ferrite basis