US3745046A - Method for producing bubble domains in magnetic film-substrate structures - Google Patents

Method for producing bubble domains in magnetic film-substrate structures Download PDF

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Publication number
US3745046A
US3745046A US00101785A US3745046DA US3745046A US 3745046 A US3745046 A US 3745046A US 00101785 A US00101785 A US 00101785A US 3745046D A US3745046D A US 3745046DA US 3745046 A US3745046 A US 3745046A
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Prior art keywords
film
substrate
garnet
lattice constant
room temperature
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Expired - Lifetime
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US00101785A
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English (en)
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J Mee
D Heinz
P Elkins
P Besser
G Pulliam
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Boeing North American Inc
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North American Rockwell Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/08—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers
    • H01F10/10—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition
    • H01F10/18—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being compounds
    • H01F10/20—Ferrites
    • H01F10/24—Garnets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
    • H01F41/20—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates by evaporation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
    • H01F41/24—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates from liquids
    • H01F41/28—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates from liquids by liquid phase epitaxy

Definitions

  • a method for producing a bubble domain in a magnetic single crystal garnet film-substrate structure involves the epitaxial deposition of an iron garnet film of the proper crystallographic orientation and having a positive magnetostriction constant on a garnet substrate in which the room temperature lattice constant of the film is larger than the room temperature lattice constant of the substrate, preferably by an amount less than 0.035 angstrom.
  • This invention relates to bubble domains and more particularly to a method of forming a craze-free film having bubble domains therein.
  • bubble domain composite single crystal film-substrate structures reported in the prior art have had crazing, that is cracking, of the film, making them unsuitable for certain types of bubble domain device applications.
  • Other iron garnet film-substrate structures were observed to have domains whose magnetization directions are in the plane of the film in contrast to the desired bubble domains whose magnetization directions are perpendicular to the plane of the film.
  • a specific step in the method involves depositing a single crystal iron garnet film of the proper crystallo graphic orientation and having a positive magnetostriction constant on a substrate in which the room temperature lattice constant of the film is larger than the room temperature lattice constant of the substrate preferably by an amount less than 0.035 angstrom.
  • This invention involves a process in which a single crystal iron garnet material is chemically vapor deposited to form a film on a substrate. It is necessary that the single crystal material have the proper crystallographic orientation to take advantage of the positive magnetostriction. In addition the room lattice constant of the deposited film is larger than the room lattice constant of the substrate by an amount less than 0.035 angstrom. The resultant film-substrate structure has a craze-free film with bubble domains therein.
  • the normal source of uniaxial anisotropy observed in magnetic materials is the crystal structure of the material
  • a A 0 positive magnetostriction constants
  • the magnetostriction contribution tends to make the normal to the plane of the platelet an easy axis of magnetization if the platelet is in compression (6 O), and a hard axis if the platelet is intension (6 0)
  • a and A are the saturation values of the linear magnetostriction constants along the 100 and ll1 directions, respectively, and 0' is the stress in the plane of the material.
  • the room temperature magnetostriction constants of selected iron garnets are listed in the following table.
  • Magnetostriet-ion constant Iron garnet Amoun M1100 S1113F05012 +21 8 5 EmFeSOm +21 +1. 8 GdaFeson. O 3. 1 Tb3Fe50r2 -3. 3 +12 Dy3Fe O z -12. 5 -5. 9 HOJF85012. -3. 4 -4. U El3Fe50lZ- +2. 0 4. 9 TrnaFesoiz +1. 4 5. 2 Yb3F650i2- +1. 4 4 5 YaFesOm -1. 4 -2 4 Y3Gao.a4Fei.3uO z- 1. 4 -1 7 LugFesom 1. 4 -2 4 Some of these iron garnet materials, for example,
  • Tb F65O12 and Yb Fe O have both a negative and a positive magnetostriction constant.
  • the crystallographic orientation of the garnet film must be chosen to take advantage of the positive magnetostriction constant. In the case with Tb -R 0 material, the orientation would be ⁇ 111 ⁇ . With the Yb Fe O material, the orientation would be ⁇ 100 ⁇ .
  • the values of the magnetostriction constants of the iron garnet material, as well as its magnetization, can be varied by depositing a film containing a mixture of two or more pure iron garnets and/or by substituting other cations for iron ions.
  • the dominant source of uniaxial anisotropy is the magnetostrictive effect resulting from the stress existing in the film. This stress is due to the difference between the lattice constants and the thermal expansion coefficients of the film and substrate and may be in the form of tension or compression.
  • This invention specifically covers a method of forming a bubble domain structure by depositing a magnetic single crystal garnet film of the proper orientation and having a positive magnetostriction constant on a substrate in which the film is in compression.
  • a co-pending application to Mee et al., Ser. No. 101,- 786, filed Dec. 28, 1970 covers a method of forming a bubble domain structure by depositing a magnetic single crystal garnet film of the proper orientation and having a negative magnetostriction constant on a substrate in which the film is in tension.
  • a co-pending application to Mee et al., Ser. No. 101,- 787, filing date Dec. 28, 1970 covers a second method of forming a bubble domain structure "by depositing a magnetic single crystal garnet film of the proper orientation and having a negative magnetostriction constant on a substrate in which the film is in tension.
  • an oxide substrate' 10 is preferably subjected to a chemical vapor deposition step to provide a thin film of magnetic bubble domain material, film 12.
  • the deposition step is carried out in accordance with the co-pending application, Ser. No. 833,- 268 filed June 16, 1969 and now abandoned, and assigned to the assignee of the present invention.
  • This pending patent application is incorporated herewith by reference hereto.
  • the film 12 may be deposited by sputtering techniques or by a liquid phase epitaxial process.
  • the substrate 10 is monocrystalline garnet having a J Q O formulation wherein the J constituent of the wafer formulation is at least one element selected from the group consisting of cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, lanthanum, yttrium, calcium, and bismuth; and the Q constituent of the wafer formulation is at least one element selected from the group consisting of indium, gallium, scandium, titanium, vanadium, chromium, manganese, rhodium, zirconium, hafnium, niobium, tantalum, aluminum, phosphorus, arsenic and antimony.
  • the J constituent of the wafer formulation is at least one element selected from the group consisting of cerium, praseodymium, neodymium, prom
  • substrate materials are mixed yttrium gadolinium gallium garnet, gadolinium gallium garnet, aluminum substituted gadolinium gallium garnet, terbium gallium garnet, samarium gallium garnet, and dysprosium gallium garnet.
  • the film of the bubble domain material is a single crystal garnet film having a J Q O formulation wherein the I constituent of the film formulation has at least one element selected from the group of cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, erbium, thulium, ytterbium, and lanthanum; the Q constituent of the film formulation is taken iron and gallium, iron and indium, iron and scandium, iron and titanium, iron and vanadium, iron and chromium, and iron and manganese.
  • a preferred substrate material is samarium gallium garnet when the film material is terbium iron garnet.
  • an iron garnet film of the proper orientation and having a positive magnetostriction constant is deposited on a garnet substrate in which the room temperature lattice constant of the film is larger than the room temperature lattice constant of the substrate, preferably by an amount less than 0.035 angstrom.
  • the preferred difference between the lattice constants is of the order of 0.010 to 0.025 angstrom.
  • the lattice constant difference is about 0.035 angstrom or more, the compressive stress is so great that the compression relieves itself and the film is in tension due to the thermal expansion mismatch.
  • the film lattice constant is smaller than the substrate lattice constant, the film is in tension and there are no bubble domains since the normal to plane of the film is the hard magnetization axis and the domain magnetizations lie in the plane.
  • the difference in the coefiicients of thermal expansion between the film and the substrate contributes to the total stress present in the film.
  • the thermal expansion stress contribution is within acceptable limits as long as the coeflicient of thermal expansion of the substrate does not differ from that of the film by more than 1X10 C. between 25 C. and 1200 C.
  • a certain amount of mismatch between film-substrate room temperature lattice constants and/or thermal ex pansion characteristics is required in order to provide the stress which produces the uniaxial anisotropy necessary for bubble domain formation. If film and substrate are too closely matched in both lattice constant and thermal expansion, the proper stress necessary for bubble domain formation will not be achieved.
  • Example I A [111] film of terbium iron garnet, T-b Fe O having a lattice constant of 12.441 angstroms was deposited on a samarium gallium garnet, Sm Ga O by chemical vapor deposition techniques.
  • the lattice constant of the samarium gallium garnet was 12.436, which was smaller than that of the film by 0.005 angstrom.
  • the resultant structure had a craze-free film which had bubble domains therein.
  • Example II a [111] terbium iron garnet film was deposited in accordance with this invention on a gadolinium gallium garnet in which the film lattice constant exceeded the substrate lattice constant at room temperature by 0.065 A. The compressive stress due to the large lattice mismatch was relieved at the deposition temperature and the film is in tension due to the thermal expansion mismatch between film and substrate. This structure had no bubble domains in the film and also Had crazing on the film surface. In Example III, the film is again in tension leading to domains whose magnetization lies in the film plane.
  • Example IV shows a film in compression but having negative magnetostriction and again there were no bubble domains, only domains whose magnetization lies from the group consisting of iron, iron and aluminum, in the plane.
  • a method of producing a bubble domain containing film-substrate structure comprising the step of depositing a magnetic film of a single crystal material of the proper crystallographic orientation and having a positive magnetostriction constant on a substrate in which the magnetic film has a room temperature lattice constant which exceeds the room temperature lattice constant of the substrate at room temperature by an amount less than about 0.035 angstrom.
  • a method of producing a bubble domain containing single crystal iron garnet film-substrate structure comprising the step of depositing an iron garnet film of the proper orientation and having a positive magnetostriction constant on a substrate in which the iron garnet film has a room temperature lattice constant which exceeds the room :temperature lattice constant of the substrate by an amount less than about 0.035 angstrom.
  • a method of producing a bubble domain containing film-substrate structure comprising the step of depositing References Cited UNITED STATES PATENTS 3,617,381 11/1971 Hanak 117-235 3,525,638 8/1970 Archey 117-107.1 X 3,486,937 12/1969 Linares 117-235 X 3,429,740 2/1969 Mee 117-235 X 3,131,082 4/1964 Gambino 117-235 3,573,099 3/1971 Moore et a1 117-235 X 3,645,787 2/1972 Mee et a1.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Thin Magnetic Films (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
US00101785A 1970-12-28 1970-12-28 Method for producing bubble domains in magnetic film-substrate structures Expired - Lifetime US3745046A (en)

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US (1) US3745046A (enrdf_load_stackoverflow)
JP (1) JPS5115594B1 (enrdf_load_stackoverflow)
CA (1) CA953619A (enrdf_load_stackoverflow)
DE (2) DE2165298C3 (enrdf_load_stackoverflow)
FR (1) FR2121044A5 (enrdf_load_stackoverflow)
GB (1) GB1367122A (enrdf_load_stackoverflow)
NL (1) NL7115118A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3946372A (en) * 1974-04-15 1976-03-23 Rockwell International Corporation Characteristic temperature-derived hard bubble suppression
US4435484A (en) 1980-07-22 1984-03-06 U.S. Philips Corporation Device for propagating magnetic domains
US4657782A (en) * 1985-03-27 1987-04-14 Nippon Sheet Glass Co., Ltd. Method of forming a rare earth-iron-garnet vertically magnetized film

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57922U (enrdf_load_stackoverflow) * 1980-05-30 1982-01-06
JPS5932289A (ja) * 1982-08-17 1984-02-21 Kyowa Seisakusho:Kk 圧電素子を発信器とした遠隔制御装置

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3946372A (en) * 1974-04-15 1976-03-23 Rockwell International Corporation Characteristic temperature-derived hard bubble suppression
US4435484A (en) 1980-07-22 1984-03-06 U.S. Philips Corporation Device for propagating magnetic domains
US4657782A (en) * 1985-03-27 1987-04-14 Nippon Sheet Glass Co., Ltd. Method of forming a rare earth-iron-garnet vertically magnetized film

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JPS5115594B1 (enrdf_load_stackoverflow) 1976-05-18
DE2165298C3 (de) 1975-04-17
FR2121044A5 (enrdf_load_stackoverflow) 1972-08-18
GB1367122A (en) 1974-09-18
NL7115118A (enrdf_load_stackoverflow) 1972-06-30
DE2165298B2 (de) 1974-08-15
DE2165298A1 (de) 1972-07-06
CA953619A (en) 1974-08-27

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