Direct measurement of external magnetic fields from a single-pole-type recording head using a microloop

An experimental method and numerical analysis have been developed which can be used to directly measure the vertical component of the head field of true scale magnetic recording heads. The transducer employed is a miniature thin-film micro-inductive sensor (microloop) for which the sensitivity function has been calculated. The microloop's thin-film nature and geometry have been advantageously used in fabricating the microloop on a soft magnetic underlayer. This paper presents measurements with the microloop of head fields from single-sided perpendicular magnetic recording heads in the absence, and presence of a soft magnetic underlayer. With a numerical fitting procedure in a convolution algorithm, the perpendicular head field was obtained indirectly. By numerically deconvolving the measured microloop output with its sensitivity function, the perpendicular head field component was obtained directly.