Playback signal distortion in CPP-GMR read heads due to induced electromagnetic interference

Abstract Electromagnetic interference (EMI) induced magnetic instabilities are an influential factor which can degrade the performance of magnetic read heads. In this paper, we investigate the influences of EMI on the playback response of the current perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) read heads via micromagnetic simulations. The readback signal and the noise spectral density of the heads when subjected to the EMI were characterized. It was found that the readback signal could be significantly distorted, or become inaccurate, from the EMI through the induced spin transfer torque effect. Also, the incorrect readback signal results in a notable expansion of the noise spectral density which further impacts the head stability. Furthermore, the bit-error-rate of the head signal processing could be markedly increased by multiple EMI occurrences. Hence, the playback response distortion of the CPP-GMR read heads due to the EMI is another concerned factor for the read sensors at higher storage capacities.