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Plated Magnetic Alloys for High Frequency Operation

IP.com Disclosure Number: IPCOM000108551D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Lee, HP: AUTHOR [+2]

Abstract

Eddy currents can significantly degrade the performance of a magnetic material for high frequency applications, such as in magnetic heads and transformers. To compensate for this effect, one can decrease the conductivity (or increase the resistivity) of the magnetic layer according to its relationship with skin depth.

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Plated Magnetic Alloys for High Frequency Operation

       Eddy currents can significantly degrade the performance
of a magnetic material for high frequency applications, such as in
magnetic heads and transformers.  To compensate for this effect, one
can decrease the conductivity (or increase the resistivity) of the
magnetic layer according to its relationship with skin depth.

      A common method to increase the resistivity of the plated
magnetic film such as permalloy is by using additives in the plating
bath so that the resistivity of the plated film increases as the
additive or a component of the additive is incorporated in the film.
Disclosed is an idea of using phosphorus acid as an additive to the
permalloy plating bath so that a small amount of phosphorus will be
incorporated in the film.

      Hypophosphite is one of the reducing agents added to nickel
plating baths in order to formulate a metastable "electroless"
plating bath.  Under the right conditions of temperature and pH,
nickel will deposit spontaneously on an activated surface, giving a
deposit of nickel-phosphorus alloy.  This film can be non-magnetic
when the phosphorus content is high enough, usually greater than 10%.
In the electroless deposition process, hypophosphite is oxidized to
phosphite, and temperatures of 80 to 90~C are needed to get
reasonable deposition rates.  At room temperature the electroless
deposition rate is negligible, but nickel electrodeposited from such
a bath still contains measurable phosphorus, which u...