Manufacture method of high coercivity FePt-Si3N4 granular composite thin films
First Claim
1. A method for producing high coercivity FePt—
- Si3N4 granular composite thin film, comprising the steps of;
(a) co-sputtering an FePt target and a Si3N4 target on a substrate by use of a conventional magnetron sputtering system to form a deposited film;
(b) annealing the film in a vacuum under controlled conditions for an annealing temperature and time period; and
(c) quenching the film in a quenching liquid to form a post-annealed FePt—
Si3N4 granular film having magnetic properties of Ms>
375 emu/cm3 and Hc>
2000 Oe, respectively.
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Abstract
A method of producing high coercivity FePt—Si3N4 granular composite thin films for magnetic recording media is invented. The method includes magnetron co-sputtering of FePt and Si3N4 targets at controlled sputtering power and sputtering argon gas pressure to form a selective composition of granular FePt—Si3N4 thin film on a low temperature substrate, then post-annealed in vacuum at selective time period and temperature. Two kinds of FePt targets can be used. One is the FePt alloy target. The other one is a composite target consisting of an iron disk overlaid with small Pt pieces. This arrangement provides a wide range of effective target compositions and therefore film compositions. FePt—Si3N4 films were deposited on natural oxidized silicon wafer or quartz glass substrate at room temperature. The as-deposited film has soft magnetic properties and granular structure with soft magnetic γ-FePt particles dispersed in amorphous Si3N4 matrix. The as-deposited film cannot be used as magnetic recording medium due to its low coercivity. After annealing at controlled conditions for a desirable temperature and time period in vacuum, the film also has granular structure but the magnetic soft γ-FePt phase is transformed into magnetic hard γ1-FePt phase. This film has high coercivity and its magnetic easy-axis is parallel to the film plane. It may be used as high-density magnetic recording medium.
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Citations
19 Claims
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1. A method for producing high coercivity FePt—
- Si3N4 granular composite thin film, comprising the steps of;
(a) co-sputtering an FePt target and a Si3N4 target on a substrate by use of a conventional magnetron sputtering system to form a deposited film;
(b) annealing the film in a vacuum under controlled conditions for an annealing temperature and time period; and
(c) quenching the film in a quenching liquid to form a post-annealed FePt—
Si3N4 granular film having magnetic properties of Ms>
375 emu/cm3 and Hc>
2000 Oe, respectively.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
- Si3N4 granular composite thin film, comprising the steps of;
Specification