Method for the rapid measurement of magnetoresistive read head dimensions

#1. Field of the Invention

#This invention relates generally to magnetoresistive (MR) read head sensing elements for magnetic data recording devices and, more particularly, to a rapid MR read head width measurement technique suitable for use during manufacture of data recording head assemblies.

#2. Description of the Related Art

#For a more complete understanding of this invention, reference is now made to the following detailed description of the embodiments as illustrated in the accompanying drawing, in which like reference designations represent like features throughout the several views and wherein:

#FIG. 1 shows a schematic diagram illustrating the various dimensions and features of the MR stripe used as a read head sensor;

#FIG. 2 illustrates a plan view of a typical MR read sensor element known in the art;

#FIG. 1 shows a magnetoresistive (MR) read sensor strip geometry known in the art. In its simplest form, the MR sensor element consists of a narrow stripe 20 of magnetoresistive materials such as NiFe, NiCo or CoFe, of height SH and width RW. The stripe 20 is mounted in a plane perpendicular to the recording medium 22 and connected to the conductors 24 at each end carrying a sense current Is. Because of the magnetoresistive effect, the resistivity of each portion of stripe 20 depends on the angle θ between the direction of magnetization Ns and the current density vector, as is well-known in the art. In a spin valve sensor, the resistivity varies as a function of the angle between the magnetic moments of the free and pinned layers.

#Thin film techniques are widely used for fabricating MR sensor elements because of the advantageous effects of very narrow read-with (RW) and stripe height (SH). FIG. 2 shows a top plan view of a MR sensor element 26. MR sensor 26 includes the stripe 20. Referring to FIG. 4, the conductor and hard bias layers 28 and 30 and the conductor and hard bias layers 31 and 32 are coupled to MR sensor element 26 in a spatial relationship that defines the read-width RW. Hard bias layers 30 and 32 are included to stabilize the magnetic domains of MR sensor element 26 in the well-known manner. The read/write head 40 also includes an upper MR shield 34 and a lower MR shield 38 (shown in FIG. 3; only MR shield 34 is shown in FIG. 2 because lower MR shield 38 is directly below). The sensor leads 36 are thin gold conductors for conducting bias current through MR sensor element 26 via conductor layers 28 and 31 and hard bias layers 30 and 32.

#FIG. 3 shows a read/write head assembly 40 viewed from the side. Read/write head 40 includes MR sensor element 26 discussed above in connection with FIG. 2 and a separate inductive write assembly 43 formed adjacent one another on a substrate 44 A portion of the read/write head 40 is shown in transducing relationship with the moving magnetic recording medium 22. The head air bearing surface (ABS) 42 is disposed in facing relationship with and slightly above the recording surface of recording medium 22. Typically, read/write head 40 (FIG. 3) represents a single pair of read and write elements (MR sensor element 26 and inductive write assembly 43). MR sensor element 26 is enclosed by upper MR shield 34 and lower MR shield 38. Sensor leads 36 (shown in FIG. 2) couple MR sensor element 26 to external circuitry (not shown) to provide for sensing the resistance of MR sensor element 26 as changed by external magnetic fields.