Magnetoresistive head with minimal electromigration

A method for reading data from a magnetic medium using a magnetoresistive head comprising:

• flowing a unidirectional sense current through a magnetoresistive element;
• determining whether one or more switching criteria have been met;
• and
• applying a counter-directional compensation current in said magnetoresistive element when said one or more switching criteria are met,
• such that electromigration in said magnetoresistive element is substantially reduced in the direction of said sense current;
• wherein said sense current and said compensation current are periodically alternated during the operation of the magnetic head;
• wherein determining whether one or more switching criteria have been met includes setting a maximum time limit for said sense current that is not exceeded prior to applying a compensation current;
• and
• further including establishing a switching criterion wherein a substantially linear relationship is set between the logarithm of said maximum time limit and the inverse of temperature, as follows:
• Log Time Max=A(1/T)-B,
• where A and B are constant values.

A magnetoresistive head for reading data from a magnetic medium comprising:

• a magnetoresistive element through which a continuous unidirectional sense current is flown;
• a control circuit for determining whether one or more switching criteria have been met, and for suspending said sense current in said magnetoresistive element for a period of time, so as to prevent atomic excursion beyond a predefined number of atom diameters;
• wherein electromigration in said magnetoresistive element is substantially reduced in the direction of said sense current;
• and
• wherein said atomic excursion is less than approximately one atom diameter.

A magnetoresistive head for reading data from a magnetic medium using a magnetoresistive head comprising:

• flowing a continuous unidirectional sense current through a magnetoresistive element;
• determining whether one or more switching criteria have been met;
• suspending said sense current in said magnetoresistive element for a period of time, so as to prevent atomic excursion beyond a predefined number of atom diameters,
• wherein electromigration in said magnetoresistive element is substantially reduced in the direction of said sense current;
• and
• wherein suspending includes suspending said sense current for a sufficient time to prevent atomic excursion beyond approximately one atom diameter.

A magnetoresistive head for reading data from a magnetic medium, comprising:

• a magnetoresistive element through which a unidirectional sense current is flown;
• and
• a control circuit for determining whether one or more switching criteria have been met and for applying a counter-directional compensation current in said magnetoresistive element when said one or more switching criteria are met,
• such that electromigration in said magnetoresistive element is substantially reduced in the direction of said sense current;
• wherein said sense current and said compensation current are periodically alternated during the operation of the magnetic head;
• wherein said control circuit determines a maximum time limit for said sense current that is not exceeded prior to applying a compensation current;
• and
• wherein said control circuit establishes a switching criterion whereby a substantially linear relationship is set between the logarithm of said maximum time limit and the inverse of temperature, as follows:
• Log Time Max=A(1/T)-B,
• where A and B are constant values.