US4316228A
Expired / Lapsed
US
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Magnetic head
Assignee: Hitachi Ltd
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Filing: 1979-12-03
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Granted: 1982-02-16
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Expires: 1999-12-03
Abstract
Abstract In a magnetic head a single-crystal Mn-Zn ferrite is employed as a core material, and cut-away parts in the vicinities of a gap are filled with a glass the contraction rate of which is lower than that of the ferrite. A principal magnetic circuit-forming plane of the core is brought into agreement with the {1 1 0} plane of the ferrite, while an angle theta defined between the <1 0 0> direction within the {1 1 0} plane of the ferrite and a gap forming plane is made 5 DEG -40 DEG or 80 DEG -120 DEG . The magnetic head thus constructed exhibits very favorable write and read characteristics.
Inventors
- 👤 Hideo Fujiwara
- 👤 Mitsuhiro Kudo
- 👤 Teizou Tamura
- 👤 Nobuyuki Sugishita
- 👤 Yoshihiro Shiroishi
- 👤 Takeshi Kimura
- 👤 Kiminari Shinagawa
- 👤 Noriyuki Kumasaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:07
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2658; G; G11; G11B; G11B5/00; G11B5/127; G11B5/133; G11B5/187; G11B5/193
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
157 words
A magnetic head comprising two magnetic blocks of high permeability which oppose to each other with a gap intervening therebetween, at least one of said magnetic blocks of high permeability being made of a single-crystal Mn--Zn ferrite, a {1 1 0} plane of the at least one single-crystal Mn--Zn ferrite being made substantially parallel to a principal magnetic circuit-forming plane, an angle θ between a <1 0 0> direction existent within said {1 1 0} plane and a plane forming said gap being made 5°-40° or 80°-120°, a glass being attached by fusion onto at least surfaces of the high-permeability magnetic block in the vicinities of sides of said gap, said glass having a lower contraction rate than said ferrite in a case of lowering the temperatures thereof from a glass setting temperature to a room temperature, and wherein a magnetocrystalline anisotropy constant K 1 of said single-crystal Mn--Zn ferrite is -2×10 4 to 1×10 4 erg/cc.
Claim 2
Dependent Claim
157 words
A magnetic head comprising two magnetic blocks of high permeability which oppose to each other with a gap intervening therebetween, at least one of said magnetic blocks of high permeability being made of a single-crystal Mn--Zn ferrite, a {1 1 0} plane of the at least one single-crystal Mn--Zn ferrite being made substantially parallel to a principal magnetic circuit-forming plane, an angle θ between a <1 0 0> direction existent within said {1 1 0} plane and a plane forming said gap being made 5°-40° or 80°-120°, a glass being attached by fusion onto at least surfaces of the high-permeability magnetic block in the vicinities of sides of said gap, said glass having a lower contraction rate than said ferrite in a case of lowering the temperatures thereof from a glass setting temperature to a room temperature, and wherein a magnetocrystalline anisotropy constant K 1 of said single-crystal Mn--Zn ferrite is -2×10 4 to 1×10 4 erg/cc.
Claim 3
Dependent Claim
16 words
A magnetic head according to claim 1, wherein said angle θ is made 10°-35° or 85°-115°.
Claim 4
Dependent Claim
16 words
A magnetic head according to claim 1, wherein said angle θ is made 20°-30° or 95°-105°.
Claim 5
Dependent Claim
18 words
A magnetic head according to claim 1, wherein said angle θ is made approximately 25° or approximately 100°.
Claim 6
Dependent Claim
50 words
A magnetic head according to claim 1, 2, 3 or 4, wherein a value obtained by subtracting the contraction rate of said ferrite from the contraction rate of said glass in the case of lowering the glass setting temperature to the room temperature is -0.2×10 -3 to -1.3×10 -3 .
Claim 7
Dependent Claim
30 words
A magnetic head according to claim 1, 2, 3 or 4, wherein a magnetocrystalline anisotropy constant K 1 of said single-crystal Mn--Zn ferrite is -1.5×10 4 to 8×10 3 erg/cc.
Claim 8
Dependent Claim
171 words
A magnetic head comprising two magnetic blocks of high permeability which oppose to each other with a gap intervening therebetween, at least one of said magnetic blocks of high permeability being made of a single-crystal Mn--Zn ferrite, a {1 1 0} plane of the at least one single-crystal Mn--Zn ferrite being made substantially parallel to a principal magnetic circuit-forming plane, an angle θ between a <1 0 0> direction existent within said {1 1 0} plane and a plane forming said gap being made 5°-40° or 80°-120°, a glass being attached by fusion onto at least surfaces of the high-permeability magnetic block in the vicinities of sides of said gap, said glass having a lower contraction rate than said ferrite in a case of lowering the temperatures thereof from a glass setting temperature to a room temperature to generate a tensile stress within the ferrite in the vicinity of the gap, and wherein a magnetocrystalline anisotropy constant K 1 of said single-crystal Mn--Zn ferrite is -2×10 4 to 1×10 4 erg/cc.
Claim 9
Dependent Claim
171 words
A magnetic head comprising two magnetic blocks of high permeability which oppose to each other with a gap intervening therebetween, at least one of said magnetic blocks of high permeability being made of a single-crystal Mn--Zn ferrite, a {1 1 0} plane of the at least one single-crystal Mn--Zn ferrite being made substantially parallel to a principal magnetic circuit-forming plane, an angle θ between a <1 0 0> direction existent within said {1 1 0} plane and a plane forming said gap being made 5°-40° or 80°-120°, a glass being attached by fusion onto at least surfaces of the high-permeability magnetic block in the vicinities of sides of said gap, said glass having a lower contraction rate than said ferrite in a case of lowering the temperatures thereof from a glass setting temperature to a room temperature to generate a tensile stress within the ferrite in the vicinity of the gap, and wherein a magnetocrystalline anisotropy constant K 1 of said single-crystal Mn--Zn ferrite is -2×10 4 to 1×10 4 erg/cc.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-02-15 | 1985-08-17 | 1986-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-15 | 1989-08-17 | 1990-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-15 | 1993-08-17 | 1994-02-16 | $7700.00 | Window Closed / Lapsed |