Sensitive element and method for manufacturing the same, and a magnetic head using the magnetic sensing element, the encoder apparatus, and a magnetic storage device

In sensitive element, an insulating film sandwiched between the two ferromagnetic films of the ferromagnetic tunnel junction is formed by an aluminum nitride film, the barrier height of the ferromagnetic tunnel junction below 0.4 eV. Aluminum nitride film, nitriding an aluminum film, in particular formed by the aluminum film by contacting the atomic nitrogen N As a result, a highly sensitive sensitive element having a tunnel magnetoresistance ratio is high and the tunnel resistance low ferromagnetic tunnel junction.