Providing a substrate, growing a ferromagnetic layer on the substrate, growing a tunnel barrier layer over the ferromagnetic layer, the step providing a first non-magnetic metal contact over the ferromagnetic layer and by a method comprising the step of providing a second non-magnetic metal contacts for a single ferromagnetic layer, a spin valve structure showing a layer structure utilized for the magnetic tunnel junction is provided. In addition to such single-sided structure, the upper surface of semi-insulating GaAs substrate, for example, _{Ga 0.94 Mn 0.06 As /} undoped _{GaAs / Ga 0.94 Mn 0.06 As3} layer structure and undoped LT it is possible to provide a double-sided structure having a -GaAs buffer layer. There is an inner square contact with the surrounding electrical back contact. According to this example structure, it is possible to perform the second probe type magnetoresistive measured through both of the ferromagnetic bodies and GaAs tunnel barrier. Resistance of the device occupies a sufficient advantage by a vertical tunneling process through the tunnel barrier.