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US5523173A
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Magnetic recording medium with a CoPtCrB alloy thin film with a 1120 crystallographic orientation deposited on an underlayer with 100 orientation
Assignee: HGST Netherlands BV
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Filing: 1994-12-27
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Granted: 1996-06-04
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Expires: 2014-12-27
Abstract
Abstract A high-density longitudinal recording medium comprising a CoPtCrB alloy with a chromium content in excess of 17 atomic percent exhibits high coercivity, low noise, and high Curie temperatures. Films are prepared by sputter depositing a chromium or chromium alloy underlayer on a non-magnetic substrate. A strong [100] crystallographic orientation of the underlayer is required to achieve a low noise, high coercivity medium. This orientation is achieved by depositing the underlayer on a negatively biased substrate under high temperature, low pressure conditions. The oriented underlayer prevents the subsequently deposited CoPtCrB alloy from orienting itself in its preferred, c axis vertical orientation. The CoPtCrB alloy comprises 4 to 12 percent platinum, 18 to 23 percent chromium and 2 to 10 percent boron.
Inventors
- 👤 Mary F. Doerner
- 👤 Brent D. Hermsmeier
- 👤 Tadashi Yogi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:45
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/657; G11B5/84; G11B5/8404; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12854; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
94 words
A thin film magnetic recording medium comprising: a non-magnetic substrate; and a non-magnetic underlayer comprising chromium sputter deposited over said substrate at a pressure of 3 to 8 mtorr while said substrate is maintained at a negative bias substantially in the range of 200 to 400 volts, said underlayer having a substantially [100] crystallographic orientation; and a thin film comprising cobalt, platinum, chromium, and boron formed on said underlayer, said thin film having a substantially [1120] crystallographic orientation and a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, and 10≧z≧2.
Claim 2
Dependent Claim
94 words
A thin film magnetic recording medium comprising: a non-magnetic substrate; and a non-magnetic underlayer comprising chromium sputter deposited over said substrate at a pressure of 3 to 8 mtorr while said substrate is maintained at a negative bias substantially in the range of 200 to 400 volts, said underlayer having a substantially [100] crystallographic orientation; and a thin film comprising cobalt, platinum, chromium, and boron formed on said underlayer, said thin film having a substantially [1120] crystallographic orientation and a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, and 10≧z≧2.
Claim 3
Dependent Claim
14 words
The thin film magnetic recording medium of claim 1 wherein said underlayer comprises chromium-vanadium.
Claim 4
Dependent Claim
14 words
The thin film magnetic recording medium of claim 2 wherein 10≧x≧6, 22≧y≧20, and 6≧z≧4.
Claim 5
Dependent Claim
22 words
The thin film recording medium of claim 2 wherein said substrate has a temperature of 200°-250° C. during deposition of said underlayer.
Claim 6
Dependent Claim
22 words
The thin film magnetic recording medium of claim 2 wherein said underlayer is deposited at a pressure of 4 to 6 mtorr.
Claim 7
Dependent Claim
65 words
A thin film magnetic recording medium comprising: a non-magnetic substrate; and a non-magnetic underlayer comprising chromium formed over the substrate, said underlayer having a substantially [100] crystal orientation; a thin film comprising cobalt, platinum, chromium, and boron formed on said underlayer, said thin film having a substantially [1120] crystal orientation and a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, 10≧z≧2.
Claim 8
Dependent Claim
65 words
A thin film magnetic recording medium comprising: a non-magnetic substrate; and a non-magnetic underlayer comprising chromium formed over the substrate, said underlayer having a substantially [100] crystal orientation; a thin film comprising cobalt, platinum, chromium, and boron formed on said underlayer, said thin film having a substantially [1120] crystal orientation and a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, 10≧z≧2.
Claim 9
Dependent Claim
14 words
The thin film magnetic recording medium of claim 6 wherein said underlayer comprises chromium-vanadium.
Claim 10
Dependent Claim
14 words
The thin film magnetic recording medium of claim 6 wherein 10≧x≧6, 22≧y≧20, and 6≧z≧4.
Claim 11
Dependent Claim
119 words
A magnetic recording disk drive comprising: a recording disk comprising; a non-magnetic substrate; and a non-magnetic underlayer comprising chromium sputter deposited over said substrate at a pressure of 3 to 8 mtorr while said substrate is maintained at a negative bias substantially in the range of 200 to 400 volts, said underlayer having a substantially [100] crystallographic orientation; and a thin film comprising cobalt, platinum, chromium, and boron formed on said underlayer, said thin film having a substantially [1120] crystallographic orientation and a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, and 10≧z≧2; and means for moving a transducer relative to said recording disk for reading data from or writing data to said recording disk.
Claim 12
Dependent Claim
119 words
A magnetic recording disk drive comprising: a recording disk comprising; a non-magnetic substrate; and a non-magnetic underlayer comprising chromium sputter deposited over said substrate at a pressure of 3 to 8 mtorr while said substrate is maintained at a negative bias substantially in the range of 200 to 400 volts, said underlayer having a substantially [100] crystallographic orientation; and a thin film comprising cobalt, platinum, chromium, and boron formed on said underlayer, said thin film having a substantially [1120] crystallographic orientation and a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, and 10≧z≧2; and means for moving a transducer relative to said recording disk for reading data from or writing data to said recording disk.
Claim 13
Dependent Claim
13 words
The magnetic recording disk drive of claim 9 wherein said underlayer comprises chromium-vanadium.
Claim 14
Dependent Claim
13 words
The magnetic recording disk drive of claim 9 wherein 10≧x≧6, 22≧y≧20, and 6≧z≧4.
Claim 15
Independent Claim
87 words
A method for producing a thin film magnetic recording medium on a substrate, comprising the steps of: sputter depositing a non-magnetic underlayer comprising chromium over said substrate at a pressure of 3 to 8 mtorr while said substrate is maintained at a negative bias substantially in the range of 200 to 400 volts; and sputter depositing a thin film comprising cobalt, platinum, chromium, and boron on said underlayer from sputtering targets having a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, and 10≧z≧2.
Claim 16
Independent Claim
87 words
A method for producing a thin film magnetic recording medium on a substrate, comprising the steps of: sputter depositing a non-magnetic underlayer comprising chromium over said substrate at a pressure of 3 to 8 mtorr while said substrate is maintained at a negative bias substantially in the range of 200 to 400 volts; and sputter depositing a thin film comprising cobalt, platinum, chromium, and boron on said underlayer from sputtering targets having a composition of CoPt x Cr y B z , wherein 12≧x≧4, 23≧y≧18, and 10≧z≧2.
Claim 17
Dependent Claim
10 words
The method of claim 12 wherein said underlayer comprises chromium-vanadium.
Claim 18
Dependent Claim
10 words
The method of claim 12 wherein 10≧x≧6, 22≧y≧20, and 6≧z≧4.
Claim 19
Dependent Claim
19 words
The method of claim 12 wherein said substrate has a temperature of 200°-250° C. during deposition of said underlayer.
Claim 20
Dependent Claim
18 words
The method of claim 12 wherein said underlayer is deposited at a pressure of 4 to 6 mtorr.
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