Magnetic field measurement for analysis of GHz response in SPT head using electron beam tomography

We measured the main pole field using electron beam tomography to analyze the GHz response of a single-pole-type (SPT) write head. The response of the head to a current was measured up to 1.3 GHz using a head without a recording medium. The magnetic field profiles around the main pole were obtained with 25-nm spacing from the head surface. The head response followed the current switching with a rise time of 0.3 ns, and the frequency response performance did not show any critical degradation up to 1.3 GHz. There was no difference in the head responses between the SPT head and a longitudinal recording head.