3-D Sensitivity Function of Shielded Reader by Reciprocity Principle

The sensitivity function to recognize the gapped or shielded reader structure is critical for quantitative analysis of the readback waveform. Although the 3-D finite-element method (FEM) model can capture the full features of geometry and material properties of the reader, it is still preferred to have the precise analytical model as a fast tool for reader design and optimization. This work proposes an analytical model to describe the readback sensitivity function of a shielded reader by the reciprocity principle whereby the media flux absorptions by the sensor free layer and shields are based on the magnetic fields generated when they are treated as the writing elements. Using this approach, the reader geometry and also the material properties of shields and free layer can be included in the model. The proposed 3-D sensitivity function of the model allows us to examine the criteria for read head design and evaluate the reading performance through the analysis of readback waveforms.