On the fly write head flyheight detector

摘要

Embodiments of the invention measure a flying height of a recording head. According to one embodiment, in a magnetic circuit comprising a recording head and a magnetic disk, a magnetic resistance changes when a flying height of a recording head fluctuates. A change in an impedance of a recording circuit is measured by making use of a recording current flown in a recording head when recording data indicates a change of a flying height of the recording head during data recording. The measured flying height can be used for stabilizing a recording operation in the magnetic disk device. This method is especially effective in a magnetic disk device based on the perpendicular magnetic recording system because an impedance largely changes in this type of magnetic disk device.