Abstract: A magnetic tunneling effect device capable of displaying a so-called magnetic tunneling effect in stability, more specifically, a magnetic tunneling junction device in which a first magnetic metal layer and a second magnetic metal layer are connected together by ferromagnetic tunnel junction via an insulating layer and in which the conductance of the tunnel current is changed by the relative angle of magnetization of these magnetic metal layers. The ferromagnetic tunnel junction has a junction area of not larger than 1 10−9 m2. For reliably controlling the junction area of the ferromagnetic tunnel junction, the insulating layer is formed by a first insulating layer for ferromagnetic tunnel junction and a second insulating layer formed on the first insulating layer for controlling the junction area of the ferromagnetic tunnel junction.

Abstract: A magneto-resistance effect device (MR device) in which stable magneto-resistance characteristics may be achieved even if a layer of a soft magnetic material is reduced in width. The MR device includes a layer of a soft magnetic material 1, a rear end electrode 4, connected to one longitudinal end of the layer of a soft magnetic material 1, and a forward end electrode 5 connected to the opposite end of the soft magnetic material 1. On both ends of the layer of the soft magnetic material 1 are arranged magnetic domain stabilizers 2, 3 generating a bias magnetic field having a component parallel to the direction of width of the layer of a soft magnetic material 1. If the bias magnetic field sufficient to overcome the longitudinal magnetostatic anisotropy can be impressed, the direction of magnetization D.sub.f of the mono-layer soft magnetic material 1 is oriented in the direction of width.

Abstract: A magneto-resistance effect film of an artificial lattice film structure having an alternate lamination of a conductor layer and a magnetic layer, or a magneto-resistance effect film of a spin bulb structure having a lamination of a magnetic layer, a conductor layer and a magnetic layer in that order. The conducting layer is mainly composed of an element selected from the group consisting of Cu, Ag and Cr and also contains 0.1 to 30 atomic percent of an addition element having an upper limit of solid solution at room temperature with respect to the element as the main component of not more than 1 percent. Alternatively, the magnetic layer is mainly composed of Fe, Co or Ni and also contains 0.1 to 30 atomic percent of an addition element having an upper limit of solid solution at room temperature with respect to the element as the main component of not more than 1%. Additionally, the thermal resistance can be improved by utilizing a base plate with a heat conductivity of not less than 2 W/mK.