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Low Inductance Magnetic Write Head

IP.com Disclosure Number: IPCOM000115697D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Ju, K: AUTHOR [+5]

Abstract

In order to increase the maximum operating frequency of a magnetic write head, the inductance needs to be minimized. This proposal identifies individual features which contribute to the total head inductance and shows modifications which will lower the inductance by 40%. These modifications do not significantly impact the construction of the head or its magnetic performance. The Table shows the individual contributions of inductance by feature. Constituents of the Head Inductance Inductance (nH) * Coil (8 turns) 11 * Yoke/Gap 28 * Shield (Coil Image) 11 * P2 Overpass 35 Element Total 85

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Low Inductance Magnetic Write Head

      In order to increase the maximum operating frequency of a
magnetic write head, the inductance needs to be minimized.  This
proposal identifies individual features which contribute to the total
head inductance and shows modifications which will lower the
inductance  by 40%.  These modifications do not significantly impact
the construction of the head or its magnetic performance.  The Table
shows the individual contributions of inductance by feature.
      Constituents of the Head Inductance
                 Inductance (nH)
  * Coil (8 turns)        11
  * Yoke/Gap              28
  * Shield (Coil Image)   11
  * P2 Overpass           35
         Element Total    85

      It is proposed that the inductance of the head can be lowered
by eliminating the inductance contribution of the P2 overpass and
part of the inductance due to the shield.  Replacement of the NiFe in
the P2 overpass with plated Cu done in a separate step eliminates
that contribution to the inductance.  Shrinking the first shield so
that the back half of the coil is not interacting with a magnetic
material also lowers the inductance.  The final inductance of such a
new design is 60% of the original inductance.