Reduction of contact noise in single-ended magnetoresistive read elements
View Patent ↗A single-element magnetoresistive (MR) read head with reduced susceptibility to noise is disclosed. In particular, the present invention addresses the problem of noise generated thermally through contact with the recording medium. The present invention solves this problem by keeping the temperature of the read head at a level that minimizes the noise level. According to a preferred embodiment of the present invention, the shielding material used in the read head is recessed with respect to the magnetic-medium-bearing surface. In an alternative embodiment of the present invention, a thin coating of metal on the read head surface is applied. In yet another embodiment, the read element is operated with a low bias current so as to minimize the thermal effect of power consumption due to electrical resistance. In still another embodiment, the read element makes use of insulating material that is both an electrical insulator and a high quality thermal insulator.
1. A magnetic read element comprising:
a layer of magnetoresistive material having a first side, a second side, and an active side;
a first layer of insulating material in contact with the first side of the layer of magnetoresistive material, wherein the first layer of insulating material is a thermal insulator;
a second layer of insulating material in contact with the second side of the layer of magnetoresistive material, wherein the second layer of insulating material is a thermal insulator;
a first layer of shielding material in contact with the first layer of insulating material;
a second layer of shielding material in contact with the second layer of insulating material; and
said magnetic read element having an active side that includes the active side of said magnetoresistive material, and further comprises a substantially planar surface disposed to face a recording medium in closely spaced relationship, said active side of said magnetic read element having two orthogonal dimensions comprising a total shield distance and an element width, respectively, wherein the element width is no greater than the total shield distance.
2. The magnetic read element of claim 1 , wherein:
each of said first and second layers of insulating material is both an electrical insulator and a thermal insulator.
3. The magnetic read element of claim 1 , wherein:
said magnetic read element includes at least one closure layer having a medium bearing surface, and the first layer of shielding material and the second layer of shielding material are recessed from a plane defined by the medium bearing surface.
4. The magnetic read element of claim 3 , wherein:
the first layer of shielding material and the second layer of shielding material are recessed by a distance sufficient to inhibit heat transfer between the first layer of shielding material and a magnetic medium and inhibit heat transfer between the second layer of shielding material and the magnetic medium, such that a temperature of the first layer of shielding material and a temperature of the second layer of shielding material fluctuate within a predetermined range.
5. The magnetic read element of claim 4 , wherein:
the at least one closure layer is separated from at least one of the first layer of shielding material and the second layer of shielding material by insulating material.
6. The magnetic read element of claim 1 , wherein:
a thermally conductive material is placed in thermal contact with the active side of the magnetoresistive material.
7. The magnetic read element of claim 6 , wherein:
the thermally conductive material is a metal.
8. The magnetic read element of claim 7 , wherein:
the metal is gold.