Parameter Effects on Thermal Protrusions of Magnetic Head Sliders

The heat transfer in the magnetic head sliders in hard disk drives, the thermal protrusion (TPR) of the head elements, and the flying height change of such sliders were numerically simulated. A simulated temperature distribution of the air-bearing surface correlated well with our experimental results. A parameter study showed that decreasing the thickness of the alumina base coat or increasing the size of the pole and shields of the head elements can reduce the magnitude of write-current-induced protrusion (W-TPR). However, a longer pole and shields increase ambient-temperature-induced protrusion (T-TPR). For W-TPR, the reduced flying height of the slider is partly compensated for by increased air pressure on the air-bearing surface. However, almost the entire magnitude of T-PTR translates into a reduction in flying height.