Measuring magnetic field saturation and its site dependence in a recording head with a magnetic force microscope

We directly imaged magnetic field saturation from the gap corners of a recording head by using magnetic force microscopy (MFM). We measured the magnetic force interactions associated with the variation of the magnetic field with respect to the applied current with high spatial resolution and studied the site dependence of the saturation behavior of the head. Our experiments show that the magnetic field saturation starts at current values as low as 3 mA at the gap edge corners of the head, while the gap edge center saturated at about 10 mA.