Writing induced nanodeformation and its effects on head-disk clearance

Abstract

Further reducing the head-disk spacing down to 3–4 nm will be needed for future extremely high-density magnetic recording systems of areal densities of 800–1000 Gbits/sq2. On the other hand, it is important to not only reduce the head-disk spacing but also retain the stability of the head-disk interface. This article reports an observation of the spacing change caused by thermal induced nanodeformation of the slider body even when writing current and the writing frequency are just within their value range in normal writing operations. Results indicate that the combination of the internal heating generated by writing operation with the cooling effect of the airflow over the air-bearing surface leads to not only local protrusion of the area around the transducer but also the variation of the crown value of the slider and, therefore, the change of the head-disk spacing. A crown deformation model is proposed and the validity of the proposed model is confirmed by both computer modeling and experimental observations.