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Magneto-Registive-Head Tester for Simultaneous Measurement of Topography of Head Surface and High-Frequency Magnetic Sensitivity

IP.com Disclosure Number: IPCOM000114317D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Katayama, H: AUTHOR [+3]

Abstract

Magneto-Registive (MR) heads are used as a component for current and future high density hard disk drives. One of the features of the MR head is that the sensitivity of the MR element is not symmetric. Some attempts have been made to measure the microscopic sensitivity and topography of the Air Bearing Surface (ABS) of MR heads as described in the references. However, only DC or low fequency sensitivity can be measured.

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Magneto-Registive-Head Tester for Simultaneous Measurement of Topography
of Head Surface and High-Frequency Magnetic Sensitivity

      Magneto-Registive (MR) heads are used as a component for
current and future high density hard disk drives.  One of the
features of the MR head is that the sensitivity of the MR element is
not symmetric.  Some attempts have been made to measure the
microscopic sensitivity and topography of the Air Bearing Surface
(ABS) of MR heads as described in the references.  However, only DC
or low fequency sensitivity can be measured.

      The objective of this invention is to be simultaneously measure
the topography of ABS and the microscopic sensitivity of MR heads in
the range from DC to high-frequencies of several hundred KHz, using
the Scanning Tunneling Microscopy (STM) technique.

      The conceptual system diagram is shown in Fig. 1.  The
amorphous magnetic tip is attached to the Piezoelectric Transducer
(PZT) scanner 1 of a STM.  CoFeSiB amorphous wire may be used as a
tip material, since it has very high permeability.  High-frequency
current is applied to a coil 2 around the tip.  The AC field from the
coil switches the magnetization at the tip end.  For conductivity,
the surface of the MR head 3 is sputter-coated with PtPd film of
thickness 100 to 200 Angstrom.  The tip to surface distance is
maintained constant by the feedback mechnism of the STM.  The AC
signal from the MR head is detected by the lock-in amplifier 4...