A magnetoresistive sensor including a lower electrode layer, a nanotube
structure film composed of an insulator matrix and a plurality of
nanotubes dispersively arranged in the insulator matrix, a
magnetoresistive film provided on the nanotube structure film, and an
upper electrode layer provided on the magnetoresistive film. Each nanotube
is composed of a circular tubular nonmetal and a circular cylindrical
metal surrounded by the circular tubular nonmetal. The nanotube structure
film is partially etched at its central region to make conduction of the
upper electrode layer and the lower electrode layer through the
magnetoresistive film and the circular cylindrical metal of each nanotube
present at the central region.
