发明名称 |
System and method for determining whether defect in perpendicular recording disk drive is from thermal asperity or defect in magnetically soft underlayer |
摘要 |
A method for determining whether a spike in a read back signal from a read head positioned over a perpendicular recording disk having a magnetically soft underlayer (SUL) is caused by a defect in the SUL or by a thermal asperity (TA). A first read back signal with the spike is obtained in the absence of a local magnetic field near the read head. Then, a permanent magnet or electromagnet is used to induce a small local magnetic field by the read head, and a second signal is obtained. If the signals are substantially similar, a thermal asperity is indicated. Otherwise a defect in the 13 magnetically soft underlayer of the disk is indicated.
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申请公布号 |
US7271967(B2) |
申请公布日期 |
2007.09.18 |
申请号 |
US20040975259 |
申请日期 |
2004.10.28 |
申请人 |
HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V. |
发明人 |
SHI ZHUPEI;TANG LI;ZHANG JANE JIE;DUAN SHANLIN |
分类号 |
G11B27/36;G11B5/02 |
主分类号 |
G11B27/36 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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