Abstract: A method for testing a magnetic head to determine whether the magnetic head is unacceptably affected by temperature variations. The test includes testing the magnetic head at different temperatures and measuring either or both of a signal amplitude and a signal asymmetry of a signal from the magnetic head at the different temperatures. If signal amplitude or signal asymmetry vary excessively as a result of the temperature change then the head can be scrapped.

Abstract: A method for testing a magnetic head to determine whether the magnetic head is unacceptably affected by temperature variations. The test includes testing the magnetic head at different temperatures and measuring either or both of a signal amplitude and a signal asymmetry of a signal from the magnetic head at the different temperatures. If signal amplitude or signal asymmetry vary excessively as a result of the temperature change then the head can be scrapped.

Abstract: A spin valve (SV) sensor of the self-pinned type includes one or more compressive stress modification layers for reducing the likelihood that the pinning field will flip its direction. The spin valve sensor includes a capping layer formed over a spin valve structure which includes a free layer, an antiparallel (AP) self-pinned layer structure, and a spacer layer in between the free layer and the AP self-pinned layer structure. A compressive stress modification layer is formed above or below the capping layer, adjacent the AP self-pinned layer structure, or both. Preferably, the compressive stress modification layer is made of ruthenium (Ru) or other suitable material.

Abstract: A method is disclosed for testing pinned layers of magnetic disk drive read heads having at least one pinned layer, where the magnetic orientation of the pinned layers has been set in an initial direction. The method includes applying a large magnetic test field at a reverse canted reset angle. First test responses from the disk drive read heads are then measured in a small magnetic test field. A large magnetic test field is applied at normal canted reset angle. The disk drive heads are then subjected to a full suite of performance tests in a small magnetic test field to verify their acceptability. These second test responses are then compared to the first test responses to identify read heads having weakly pinned layers.

Abstract: Methods and apparatus for protecting read sensors from damage caused by electrostatic discharge (ESD) during manufacturing are described. Two electrical connections are formed and utilized for ESD protection: one primarily for early protection of the sensors (i.e. prior to cutting and lapping the wafer to form the ABS) and the other primarily for later protection of the sensors (i.e. after cutting and lapping the wafer to form the ABS). The first electrical connection is created between the read sensor and the first and second shields, and is severed when the wafer is cut and lapped along the ABS. The second electrical connection is formed between the sensor leads and the first and second shields, and is exposed on an outside surface of the magnetic head. The second electrical connection is severed late in the manufacturing process, preferably by laser-deletion.

Abstract: Methods and apparatus for protecting read sensors from damage caused by electrostatic discharge (ESD) during manufacturing are described. Two electrical connections are formed and utilized for ESD protection: one primarily for early protection of the sensors (i.e. prior to cutting and lapping the wafer to form the ABS) and the other primarily for later protection of the sensors (i.e. after cutting and lapping the wafer to form the ABS). The first electrical connection is created between the read sensor and the first and second shields, and is severed when the wafer is cut and lapped along the ABS. The second electrical connection is formed between the sensor leads and the first and second shields, and is exposed on an outside surface of the magnetic head. The second electrical connection is severed late in the manufacturing process, preferably by laser-deletion.