Browse Prior Art Database

Measuring Apparatus for the Locally Resolved Characterization of Magnetic Sensors

IP.com Disclosure Number: IPCOM000120795D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 50K

Publishing Venue

IBM

Related People

Lang, A: AUTHOR [+3]

Abstract

Using a dynamic force microscope, the sensitive area of a magnetic sensor is scanned by a magnetic measuring tip. During scanning, the vertically oscillating measuring tip produces an oscillating magnetic field. This field leads to changes in the sensor signal, which can be very accurately determined, so that local resolutions better than 1 micrometer are obtainable.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Measuring Apparatus for the Locally Resolved Characterization of
Magnetic Sensors

      Using a dynamic force microscope, the sensitive area of a
magnetic sensor is scanned by a magnetic measuring tip. During
scanning, the vertically oscillating measuring tip produces an
oscillating magnetic field.  This field leads to changes in the
sensor signal, which can be very accurately determined, so that local
resolutions better than 1 micrometer are obtainable.

      The basic concept of the described apparatus is to scan the
sensor by a fine oscillating magnetic measuring tip.  If the tip is
sufficiently close to the sensor, its signal changes in response to
the oscillating magnetic field at the respective frequency.  This
change can be very accurately determined with the aid of lock-in
technique.  This technique or measuring method is readily
implementable by a set-up similar to that of a dynamic force
microscope (Y. Martin, C. Williams and H.K. Wickramasinghe, Journal
of Applied Physics 61, 4732 (1987)) operating in two modes.
      1.   The measuring tip is scanned very closely, but without any
active space control, above the magnetic sensor, determining by means
of the oscillation amplitude whether the tip is being moved without
contact.
      2.   In the second mode, the force microscope is controlled to
keep the space between the tip and the probe surface constant.

      In either mode, the measuring value is the change in the sensor
signal e...