US3119753A - Method of preparing thin magnetic films - Google Patents

Method of preparing thin magnetic films Download PDF

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Publication number
US3119753A
US3119753A US60735A US6073560A US3119753A US 3119753 A US3119753 A US 3119753A US 60735 A US60735 A US 60735A US 6073560 A US6073560 A US 6073560A US 3119753 A US3119753 A US 3119753A
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US
United States
Prior art keywords
films
plating
hypophosphite
nickel
iron
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
US60735A
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English (en)
Inventor
Joseph S Mathias
Edwin F Schneider
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Sperry Corp
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Sperry Rand Corp
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
Priority to NL269912D priority Critical patent/NL269912A/xx
Application filed by Sperry Rand Corp filed Critical Sperry Rand Corp
Priority to US60735A priority patent/US3119753A/en
Priority to GB34704/61A priority patent/GB950342A/en
Priority to DES76109A priority patent/DE1147817B/de
Priority to CH1154261A priority patent/CH425393A/it
Priority to FR875096A priority patent/FR1302747A/fr
Application granted granted Critical
Publication of US3119753A publication Critical patent/US3119753A/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
    • G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
    • G11B5/653—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing Fe or Ni
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt
    • 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
    • H01F10/12—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys
    • H01F10/14—Thin magnetic films, e.g. of one-domain structure characterised by magnetic layers characterised by the composition being metals or alloys containing iron or nickel
    • 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
    • H01F41/26—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 using electric currents, e.g. electroplating

Definitions

  • Thin ferromagnetic films of nickel-iron alloys are used extensively for computer information storage and in switching applications. in use, it is desirable that the films have relatively square hysteresis loops and low coercive forces.
  • Various methods have been used, such as vacuum deposition of vapors of the metals and the like. It has also been proposed to prepare the thin films by electrodeposition from suitable plating solutions. The latter method has advantages, but the films produced often leave something to be desired in their properties.
  • the present invention constitutes an improved electroplating method for the formation of thin nickel-iron films.
  • the most important characteristic of the present invention is the presence of the small amount of a hypophosphite. This permits a very precise control and results in films of lower coercivity, H and B and in the hard direction the hysteresis loop opens up to a much lower degree as will be shown in the drawings. An even more important property is switching time.
  • the films of the present invention have much lower switching times under the same operating conditions than do films of the same character prepared without hypophosphite.
  • the range of hypophosphite in grams per liter is from about 0.95 to 0.4. Optimum results are obtained with hypophosphite concentrations from 0.08 to 023 g./l.
  • the pH should be maintained in the range from 1.7 to 2.8, poorer results being obtained when the pH is outside of this range. Within the range of pHs, BH properties are excellent and are uniformly reproducible.
  • Film thickness while not as critical as hypophosphite content and pH, is, nevertheless, of importance. Good results are obtained with thicknesses from 800 to 1600' A.
  • hypophosphite is not especially critical so long as it is not a platable metal.
  • sodium hypophosphite is preferred although, of course, the same results can be obtained with other alkali metal hypophosphites, such as potassium hypophosphite.
  • alkali metal hypophosphites such as potassium hypophosphite.
  • the plating procedure is otherwise normal, and does not present any particular problems.
  • the temperature is not especially critical, and room temperature may be used. There is no appreciable difference between the BH properties of films plated at room temperature and those plated at higher plating temperatures, for example in the range of 50 to 52 C. The relative insensitivity to small temperature changes makes control of the process of the present invention simple and is a desirable practical operating characteristic.
  • the nature of the substrate does not differ significantly from general plating practice by other methods.
  • a smooth conducting surface is desirable which, for example, can either be polished metal or glass metallized so that it has the necessary conductivity for electroplating.
  • the latter type of substrate has some advantages and will be described in connection with specific examples, though, of course, the invention is not in any sense limited to the particular type of substrate used.
  • the proportions of nickel and iron in the final film can be varied over wide ranges by control of the various proportions of nickel and iron salts in the plating bath. Optimum results are obtained when the proportion of iron to nickel in the bath is between 1.5 to 98.5 to 3 to 97. This results in percentages of iron in the film from slightly below 14 to about 23%. It is an advantage of the present invention that the films produced have excellent properties over a considerable range of iron to nickel proportions so that in this respect no extremely critical control of plating bath composition is necessary.
  • FIG. 1 is a series of curves of reciprocal switching times for two different films
  • FIG. 2 is a pair of BH loops for a film prepared with hypophosphite
  • FIG. 3 is a similar pair for a film prepared without phosphite.
  • Substrates were made from circular pieces of glass 9 mm. in diameter plated first with a film about a A. of chromium followed by 100 A. film of gold. Coating was by vacuum vapor deposition. The substrates were then plated in the bath in the conventional manner at room temperature using 4 to 6 volts and maintaining the current density at 6 ma./cm. pH of the various baths was varied from 1.5 to 3.4. Time of plating varied from approximately 60 seconds to about 2 minutes in order to produce films from 800 to 1600 A.
  • FIG. 1 shows curves of reciprocal switching times vs. drive for two films prepared as above, one with .3 g./l. hypophosphite and one without. It will be seen that the curves of the film prepared with the hypophosphite are much steeper than those of the other film. This permits faster switching times under any given set of drive conditions. This is of great importance in practical applications in computers and constitutes the most important advantage of films prepared by the process of the present invention.
  • FIGS. 2 and 3 illustrate hysteresis loops of the two films described above. It will be noted that in FIG. 2, which illustrates films prepared by the present invention, the loops are squarer and in the hard direction there is little or no opening of the loop. There is also a much lower coercive force shown in FIG. 2 which will be expressed in figures in following examples.
  • EXAMPLE 2 Plating was effected under conditions described in Example 1 in a series of baths having 0.3 g./l. of hypophosphite and varied amounts of ferrous sulfate. The following tabulation gives the composition of the films with change in ferrous sulfate concentration.
  • EXAMPLE 3 A series of platings were made with fixed thickness, current density, bath composition and hypophosphite content. The pHs varied from 1.5 to 3.4. The composition of the bath, film thickness and resulting film properties are as follows:
  • EXAMPLE 4 A series of platings was efiected with different amounts of sodium hypophosphite. The plating data and characteristics were as follows:
  • hypophosphite markedly reduces coercivity and improves other characteristics.
  • the nickel-iron composition ranges from between about 77% and 86% nickel, balance iron
  • the method comprises plating on a conducting substrate from a plating bath comprising nickel and iron salts, the improvement comprising adding from 0.05 to 0.4 g./l. of an alkali metal hypophosphite to the bath and maintaining the pH of the plating bath below 3.
  • alkali metal hypophosphite concentration is from 0.08 to 0.3 g./l. of hypophosphite.
  • a solution for use in electroplating nickel-iron magnetic films comprising approximately 218 g./l. of nickel sulfate, approximately 3.6-6.0 g./l. of ferrous sulfate and approximately 0.4 g./l. of sodium hypophosphite.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemically Coating (AREA)
  • Thin Magnetic Films (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)
  • Electroplating Methods And Accessories (AREA)
US60735A 1960-10-05 1960-10-05 Method of preparing thin magnetic films Expired - Lifetime US3119753A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL269912D NL269912A (ru) 1960-10-05
US60735A US3119753A (en) 1960-10-05 1960-10-05 Method of preparing thin magnetic films
GB34704/61A GB950342A (en) 1960-10-05 1961-09-27 Method of preparing thin magnetic films
DES76109A DE1147817B (de) 1960-10-05 1961-09-30 Verfahren zum galvanischen Abscheiden eines Nickel-Eisen-UEberzuges
CH1154261A CH425393A (it) 1960-10-05 1961-10-04 Procedimento per la preparazione di pellicole magnetiche sottili
FR875096A FR1302747A (fr) 1960-10-05 1961-10-05 Procédé de préparation de pellicules magnétiques minces

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US60735A US3119753A (en) 1960-10-05 1960-10-05 Method of preparing thin magnetic films

Publications (1)

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US3119753A true US3119753A (en) 1964-01-28

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Country Status (5)

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US (1) US3119753A (ru)
CH (1) CH425393A (ru)
DE (1) DE1147817B (ru)
GB (1) GB950342A (ru)
NL (1) NL269912A (ru)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3255033A (en) * 1961-12-28 1966-06-07 Ibm Electroless plating of a substrate with nickel-iron alloys and the coated substrate
US3297418A (en) * 1964-04-24 1967-01-10 Firestone Stanley Magnetic thin film element and method of manufacture
US3350180A (en) * 1967-10-31 Magnetic device with alternating lami- na of magnetic material and non-mag- netic metal on a substrate
US3354059A (en) * 1964-08-12 1967-11-21 Ibm Electrodeposition of nickel-iron magnetic alloy films
US3353986A (en) * 1963-11-20 1967-11-21 Sperry Rand Corp Electroless deposition of cobalt-ironphosphorous magnetic material
US3393982A (en) * 1962-11-08 1968-07-23 Ncr Co Ferromagnetic storage devices having uniaxial anisotropy
US3442774A (en) * 1964-03-09 1969-05-06 Ibm Method of electrodepositing a magnetic coating on a chain-like memory element
US3549508A (en) * 1965-11-19 1970-12-22 Toko Inc Process for producing magnetic thin film wire by multiple-layer electrodeposition
US3699553A (en) * 1971-02-12 1972-10-17 Us Navy Nondestructive readout thin film memory device and method therefor
US5576099A (en) * 1990-02-09 1996-11-19 International Business Machines Corporation Inductive head lamination with layer of magnetic quenching material
CN102409375A (zh) * 2011-12-01 2012-04-11 广州市海珠区金穗达表面技术发展中心 一种镍磷合金电镀液及其使用方法
CN106381510A (zh) * 2016-12-06 2017-02-08 刘志红 一种Ni‑Fe‑P合金基复合镀层的制备工艺
CN106757287A (zh) * 2016-12-06 2017-05-31 刘志红 一种Fe‑Ni‑P基复合镀层的制备工艺
CN104451829B (zh) * 2014-11-20 2017-06-27 长沙理工大学 一种镍‑铁‑磷/纳米v8c7复合电镀液

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1965399A (en) * 1929-06-25 1934-07-03 Western Electric Co Method of and apparatus for electro-chemically producing articles
US2643221A (en) * 1950-11-30 1953-06-23 Us Army Electrodeposition of phosphorusnickel and phosphorus-cobalt alloys
US2644787A (en) * 1950-01-05 1953-07-07 Eckert Mauchly Comp Corp Electrodeposition of a magnetic coating
US2945217A (en) * 1958-10-01 1960-07-12 Ncr Co Magnetic data storage devices

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1965399A (en) * 1929-06-25 1934-07-03 Western Electric Co Method of and apparatus for electro-chemically producing articles
US2644787A (en) * 1950-01-05 1953-07-07 Eckert Mauchly Comp Corp Electrodeposition of a magnetic coating
US2643221A (en) * 1950-11-30 1953-06-23 Us Army Electrodeposition of phosphorusnickel and phosphorus-cobalt alloys
US2945217A (en) * 1958-10-01 1960-07-12 Ncr Co Magnetic data storage devices

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3350180A (en) * 1967-10-31 Magnetic device with alternating lami- na of magnetic material and non-mag- netic metal on a substrate
US3255033A (en) * 1961-12-28 1966-06-07 Ibm Electroless plating of a substrate with nickel-iron alloys and the coated substrate
US3393982A (en) * 1962-11-08 1968-07-23 Ncr Co Ferromagnetic storage devices having uniaxial anisotropy
US3353986A (en) * 1963-11-20 1967-11-21 Sperry Rand Corp Electroless deposition of cobalt-ironphosphorous magnetic material
US3442774A (en) * 1964-03-09 1969-05-06 Ibm Method of electrodepositing a magnetic coating on a chain-like memory element
US3297418A (en) * 1964-04-24 1967-01-10 Firestone Stanley Magnetic thin film element and method of manufacture
US3354059A (en) * 1964-08-12 1967-11-21 Ibm Electrodeposition of nickel-iron magnetic alloy films
US3549508A (en) * 1965-11-19 1970-12-22 Toko Inc Process for producing magnetic thin film wire by multiple-layer electrodeposition
US3699553A (en) * 1971-02-12 1972-10-17 Us Navy Nondestructive readout thin film memory device and method therefor
US5576099A (en) * 1990-02-09 1996-11-19 International Business Machines Corporation Inductive head lamination with layer of magnetic quenching material
CN102409375A (zh) * 2011-12-01 2012-04-11 广州市海珠区金穗达表面技术发展中心 一种镍磷合金电镀液及其使用方法
CN104451829B (zh) * 2014-11-20 2017-06-27 长沙理工大学 一种镍‑铁‑磷/纳米v8c7复合电镀液
CN106381510A (zh) * 2016-12-06 2017-02-08 刘志红 一种Ni‑Fe‑P合金基复合镀层的制备工艺
CN106757287A (zh) * 2016-12-06 2017-05-31 刘志红 一种Fe‑Ni‑P基复合镀层的制备工艺

Also Published As

Publication number Publication date
CH425393A (it) 1966-11-30
GB950342A (en) 1964-02-26
NL269912A (ru)
DE1147817B (de) 1963-04-25

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