US3639247A - Calcium-vanadium series ferrimagnetic garnets - Google Patents

Calcium-vanadium series ferrimagnetic garnets Download PDF

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Publication number
US3639247A
US3639247A US8491A US3639247DA US3639247A US 3639247 A US3639247 A US 3639247A US 8491 A US8491 A US 8491A US 3639247D A US3639247D A US 3639247DA US 3639247 A US3639247 A US 3639247A
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values
41rms
value
compositions
temperature
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Hideo Takamizawa
Keiichi Yotsuyanagi
Takashi Okada
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NEC Corp
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Nippon Electric Co Ltd
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Priority claimed from JP44009410A external-priority patent/JPS4829119B1/ja
Priority claimed from JP44051190A external-priority patent/JPS4827117B1/ja
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    • 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
    • C04B35/2641—Compositions containing one or more ferrites of the group comprising rare earth metals and one or more ferrites of the group comprising alkali metals, alkaline earth metals or lead

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  • ABSTRACT Calcium-vanadium ferrimagnetic garnets having the compositions expressed by the formula:
  • a T TORNEYS CALClUM-VANADIUM SERIES FERRIMAGNETIC GARNETS The present invention relates to calcium-vanadium (Ca- V) series ferrimagnetic garnets for use in microwave circuit elements operating in theVHF, UHF or SHF'band range.
  • Ca- V calcium-vanadium
  • Desired values of 41rMs will vary according to the application of the magnetic materials.
  • the essential condition for reducing the magnetic loss is that the ferromagnetic resonance linewidth (AH) be as low as possible.
  • YIG yttrium-iron series garnets
  • yttrium-iron series garnets are considerably offset by defects such as the necessity for the use of yttrium oxide which is an expensive raw material and the need for sintering at extremely high temperatures and for long time intervals which are not suited for large-scale industrial production.
  • Yttrium-iron garnets substituted with A1 for lowering the saturation magnetization have an other defect of a rapid lowering of the Curie temperature which inevitably causes a large variation of 411Ms with a temperature variation.
  • magnesium-manganese series ferrites have defects such as iow Curie temperatures and the concomitant unfavorable temperature stability of the saturation magnetization.
  • the object of the present invention is to eliminate these defects and to provide microwave circuit element materials for use in the VHF, UHF or SHF band range, having excellent characteristics such as low 41rMs values of less than 800 gauss, low ferromagnetic resonance linewidth values, and high Curie temperatures.
  • the garnet compositions are generally expressed by a normal formula unit ⁇ A ⁇ [B ](C;,)O, wherein brackets ⁇ and represent respectively the 240, I60 and 24a sites and A, B and C denote atoms occupying the respective sites.
  • Fe has a preference for the two different sublattice sites (the 16a and the 24d sites) and the FeFe superinteractions in each of and between these sublattice sites cause the Fe magnetic moments at the 16a and 24d sites to be coupled antiferromagnetically. Under the situation of the relative site unbalance, wherein the magnetic moment at the 24d site is not equal to that at the 16a site, the garnet compositions manifest ferrimagnetism. It has been generally considered that the compositions manifest antiferromagnetism in case of the site balance and at which an abnormal phenomenon of AH occurs.
  • the value of 41rMs is determined by the relative site unbalance in the magnetic moment between the 16a and 24d sites for which Fe has a strong preference, while the temperature variation of 41rMs changes with the numbers of iron ions located on each sublattice site, kinds of nonmagnetic ions replacing the iron ions, and kinds of ions located on the 24c site.
  • the conventional calcium-vanadium garnet which can be expressed by a normal formula unit ⁇ Ca ⁇ [Fe ](Fe,, V, )0, was of little or no utility in that its AH values were in excess of 300 oersteds in spite of its advantage of possessing a high Curie temperature and low 41rMs values.
  • the Y-and Ge-substituted Ca-V garnets can be further substituted with Ta.
  • the garnet compositions thus obtained can be expresses as i a-u ui[ z-: zi( i.s-n.s:+o.su: z as-asx-osw-z) i2, in which x, y and z should be within the ranges 0.05 E x; 0.8, 0.05 g y E 1.4 and 0 z 0.17, and preferably the ranges 0.1-5x; 0.8, 0.05 g y 5 L4 and 0.02 g z 5 0.l7, respectively.
  • compositions satisfying the relation 0.95 g 4z+y-x 5 1.05 should be excluded. Furthermoreit is. preferable ,to'exclude awider range of compositions in-which the difference is 0.1 or less, that is 0.8 4z+yx 1.2, in view of the effect on the improve n AHL V.
  • Both of the garnet compositions of this invention may be produced by presintering a mixture of oxides of the elements to be contained in the final product or a mixture of other compounds of such elements, which are easily decomposed into the respective oxides at elevated temperature, at a tempera ture or temperatures within the range of 800 to 1,150 C. for l to 8 hours in an oxidizing atmosphere, crushing and pressmolding it, followed by sintering the molded body at a temperature or temperatures within the range of 1,160" to l,3 50" C. for l to 30 hours in an oxidizing atmosphere.
  • FIG. l is a graph of the 41rMs versus temperature characteristics of the garnet compositions of the prior art and of this invention which illustrates the advantages of this invention
  • FIGS. 2 and 3 show, respectively, ferromagnetic resonance linewidths (AH) and Curie temperatures as a function of x for the Y-and Ge-Substituted Ca-V ferrimagnetic garnets of this invention with the compositions expressed as FIGS. 4, 5 and 6 show, respectively, Curie temperatures,
  • ferromagnetic resonance linewidths (AH) and saturation magnetizations (4rrMs) as a function of y for the same compositions as in FIGS. 2 and 3;
  • FIG. 7 is a composition diagram illustrating the effective range hounded by the lines connecting the coordinates expressed by (x,y) within which the Y-and Ge-Substituted Ca-V series ferrimagnetic garnet compositions according to this in vention fall and the points of the coordinates (1, for typical garnet compositions listed in table 2;
  • FIGS. 8 and 9 are graphs respectively illustrating the incomposition possesses a lower 4bMs and a lower AH value fluence of 2 (T 0n AH and 41I'MS the compositions (AH 76 the Y, Geand Ta-substitutions have succeeded pressed as in raising the Curie temperature which was lowered by the 3U tI 2z z]( 1.50.5.t+0.5
  • FIGS. 12 and 13 are graphs illustrating the influence of y pared, which possess low 47rMS. low AH.
  • AH is increased in com- 75 tively 118, and 88 Centigrade. This indicates clearly parison with sample No. [I], it is possible to have a lower AH value with a sufiiciently high Curie temperature by changing that the rate of decrease of the Curie temperature becomes smaller with increasing y.
  • 41rMs can take any desired values less than 800 gauss with varying values of y. This is advantageous in employing the present materials in the VHF, UHF or SHF band range.
  • the yttrium-iron-aluminum series garnets and magnesium-manganese series ferrites currently used as microwave device materials have been found inadequate for the following reasons:
  • the Curie temperature approaches l00 C., for 4'n-Ms values of the order of 260 gauss, which causes an increase in the temperature variation of 41rMs and a drift of tuning points due to temperature variations. This results in a degradation in the isolation property, an increase in the VSWR, and an increase in the insertion loss.
  • this invention can provide calciumvanadium series ferrimagnetic garnets with high Curie tem- TABLE 2 Curie Deutschen Deutschenmaschinelng terncondttlons All new 41 Ms (oertun: x y C. Hrs. (gauss) sheds) C.)
  • compositions mt menses isthqss sssmx iemYsst ys1.--.-.
  • I) l2 enables high Curie temperatures and low linewidth (AH) values which are much lower than the values of AH of the unsubstituted calcium vanadium garnet compositions.
  • compositions of this invention lie, as mentioned previously, within the polygonal area A-B-C- D-E shown in FIG. 7 which is bounded by the lines connecting t sqqtd natss;
  • compositions outside the lines A-B and E-A manifest to an insufficient degree the beneficial effects of this invention to render them useful in practical applications; the compositions lying in the area above the line B-C possess low Curie temperatures less than- 100C. and large temperature variations of 41rMs, rendering them difficult for practical use, although they have improved AH values; the compositions lying outside of the line CD and having relatively small values of y possess low Curie temperatures and large temperature variations of 41rMs; in the compositions outside the line C-D and having a larger value for y, AH values are not substantially improved; the compositions lying outside of .the line D-E have high Curie temperatures, but their AH values are substantially the same as or a little inferior to the AH value of the unsubstituted Ca-V garnet compositions.
  • sintering for long time intervals at extremely elevated temperatures would be necessary, which apparently does not meet the objects of this invention.
  • substitution by Ta causes a decrease in 41rMs in spite of its small amounts.
  • the substitution is also effective for lowering the value of AH.
  • H6. 11 shows the dependence of 41rMs on x in the same case.
  • FIG. 13 illustrates the dependence of 41rMs on the value of y in the same case.
  • y i.e., yttrium substitution quantities
  • the value of 41rMs decreases.
  • the 411Ms value becomes less than 50. This point corresponds to approximately the point where the relation 4z+yFl is satisfied. It is generally considered that compositions meeting this relationship manifest antiferromagnetism and do not manifest ferrimagnetism.
  • the Curie temperatures increase with an increase in y as shown in table 5 and this increase tends to compensate for a decrease in Curie temperature caused by the combined tantalumand germanium-substitutions.
  • But an increase in y is disadvantageous in the use of large quantities of Y,O which is an expensive raw material. This inevitably renders finished material costs expensive.
  • the Ca-V series ferromagnetic garnets according to this invention offer advantages over the known yttrium-iron-aluminum garnets series of lw-41rMs microwave magnetic materials such as lower magnetic losses, higher Curie temperatures, improved 41rMs versus temperal0 D-E shown in FIG. 7 of the drawing which is bounded by the ture characteristics, lower costs which comes from the use of smaller quantities of yttrium, and also lower sintering temperatures (of the order of as low as 200 C.) than those of the aluminum-substituted YlG, which advantages can be important in large-scale industrial production.
  • compositions of the invention provide inexpensive microwave element materials forum in VHF, UHF'and SHF band ranges, the materials having low 41rMs values, improved 41rMs versus temperature characteristics, low magnetic losses and being also easily amendable to large-scale production.
  • the tantalum-germanium-yttrium substituted calcium-vanadium garnet compositions are particularly useful in this regard as follows:

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  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
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  • Magnetic Ceramics (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
US8491A 1969-02-07 1970-02-04 Calcium-vanadium series ferrimagnetic garnets Expired - Lifetime US3639247A (en)

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JP44009410A JPS4829119B1 (enrdf_load_stackoverflow) 1969-02-07 1969-02-07
JP44051190A JPS4827117B1 (enrdf_load_stackoverflow) 1969-06-27 1969-06-27

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DE (1) DE2005510A1 (enrdf_load_stackoverflow)
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GB (1) GB1242514A (enrdf_load_stackoverflow)
NL (1) NL7001758A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3763045A (en) * 1970-04-03 1973-10-02 Nippon Electric Co Calcium-vanadium ferrimagnetic garnets
US3886533A (en) * 1973-07-20 1975-05-27 Bell Telephone Labor Inc Magnetic devices utilizing garnet epitaxial material
US4125473A (en) * 1976-10-26 1978-11-14 Thomson-Csf Polycrystalline ferrimagnetic garnet having a narrow gyromagnetic resonance line width and a low magnetic moment
US4614923A (en) * 1984-02-21 1986-09-30 Selenia Industrie Elettroniche Associate Spa Method of suppressing magnetostatic waves in magnetic garnet films for microwave circuit applications

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3772963B2 (ja) 2000-08-18 2006-05-10 株式会社村田製作所 高周波用磁性体の製造方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3156651A (en) * 1962-03-28 1964-11-10 Bell Telephone Labor Inc Light transparent ferrimagnetic garnets
US3268452A (en) * 1963-07-10 1966-08-23 Bell Telephone Labor Inc Vanadium-containing garnets
US3281363A (en) * 1963-07-10 1966-10-25 Bell Telephone Labor Inc Bismuth-containing garnets and their preparation
US3291740A (en) * 1963-11-29 1966-12-13 Bell Telephone Labor Inc Ferrimagnetic garnet compositions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3156651A (en) * 1962-03-28 1964-11-10 Bell Telephone Labor Inc Light transparent ferrimagnetic garnets
US3268452A (en) * 1963-07-10 1966-08-23 Bell Telephone Labor Inc Vanadium-containing garnets
US3281363A (en) * 1963-07-10 1966-10-25 Bell Telephone Labor Inc Bismuth-containing garnets and their preparation
US3291740A (en) * 1963-11-29 1966-12-13 Bell Telephone Labor Inc Ferrimagnetic garnet compositions

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3763045A (en) * 1970-04-03 1973-10-02 Nippon Electric Co Calcium-vanadium ferrimagnetic garnets
US3886533A (en) * 1973-07-20 1975-05-27 Bell Telephone Labor Inc Magnetic devices utilizing garnet epitaxial material
US4125473A (en) * 1976-10-26 1978-11-14 Thomson-Csf Polycrystalline ferrimagnetic garnet having a narrow gyromagnetic resonance line width and a low magnetic moment
US4614923A (en) * 1984-02-21 1986-09-30 Selenia Industrie Elettroniche Associate Spa Method of suppressing magnetostatic waves in magnetic garnet films for microwave circuit applications

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GB1242514A (en) 1971-08-11
NL7001758A (enrdf_load_stackoverflow) 1970-08-11
FR2032799A5 (enrdf_load_stackoverflow) 1970-11-27
DE2005510A1 (de) 1970-12-03

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