Effects of track width and stripe height ratio on the characteristics of CPP-GMR and TMR heads

Hard disk drive industry has been facing strong competition from other data storage devices. The primary reader technology based on the Giant magnetoresistance (GMR) and Tunneling magnetoresistance (TMR). TMR head reaches the limit at the 2Tb/in
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recording density, because of its high impedance affected on the bit rate of the signal. Overcoming the previous limit, CPP-GMR reader using all metallic materials and in current perpendicular to the plane (CPP) geometry has to be employed for areal density >;2Tb/in
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. In this study we focus on physical dimension designs of CPP-GMR head. CPP-GMR still shows the potential gaps of resistance to narrow down the reader size, in terms of static signal to noise ratio (SNR), CPP-GMR shows maximum static SNR at bit aspect ratio (BAR) -0.6, which suggests that the key physical dimension track width and stripe height ratio should be optimized to achieve static SNR of CPP-GMR sensor. By the way we need to consider more about other design parameters, for examples magnetic materials, Resistance area (RA) and alternative metal spacers.