Method for controlling properties of magnetic film
Abstract
Abstract A METHOD FOR CONTROLLING MAGNETIC PROPERTIES OF MAGNETIC FILMS BY CONTROLLING THE ROUGHNESS OF THE SUBSTRATE SURFACE ONTO WHICH THE MAGNETIC FILM IS DEPOSITED. ON ONE HAND THE COERCIVITY MAY BE VARIED ALTHOUGH THE MAGNETIC FILM THICKNESS IS BEING KEPT CONSTANT, ON THE OTHER HAND CONSTANT VALUES OF COERCIVITY CAN BE OBTAINED EVEN THOUGH THE THICKNESS OF THE MAGNETIC FILM MAY VARY. THE SUBSTRATE CONSISTS OF A CONDUCTIVE GROUND PLATE COATED WITH A THIN LAYER OF INSULATING MATERIAL AND THEREAFTER COPPER PLATED. PRIOR TO THE DEPOSITION OF THE MAGNETIC FILM, THE COPPER SURFACE IS TREATED BY ELECTRO PULSE PLATING INCLUDING REVERSE PULSING TO OBTAIN A WELL DEFINED AND CONTROLLED SURFACE ROUGHNESS.
Inventors
- 👤 John V Powers
- 👤 Lubomyr T Romankiw
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |