Magnetoresistance effect element

A magnetoresistance effect element comprising:

• a first ferromagnetic metal layer;
• a second ferromagnetic metal layer;
• and
• a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers,
• wherein:
• the tunnel barrier layer has a spinel structure in which cations are arranged in a disordered manner;
• the tunnel barrier layer is expressed by a composition formula of (M1-xZnx)((T1)2-y(T2)y)O4,
• wherein M represents a non-magnetic divalent cation other than Zn,
• each of T1 and T2 represents a non-magnetic trivalent cation, and
• x and y represent a composition ratio in a region where composition ratios
• combined as follows ((1) to (5)) are vertexes, and the vertexes are connected
• by straight lines:
• (1) x=0.2, y=0.1,
• (2) x=0.8, y=0.1,
• (3) x=0.8, y=1.7,
• (4) x=0.6, y=1.7, and
• (5) x=0.2, y=0.7;
• the tunnel barrier layer comprises:
• at least one lattice-matched portion that is lattice-matched with both of the first ferromagnetic metal layer and the second ferromagnetic metal layer, and at least one lattice-mismatched portion that is not lattice-matched with at least one of the first ferromagnetic metal layer and the second ferromagnetic metal layer;
• and
• when viewed as an inverse Fourier transform image in a stacking direction of a cross-sectional crystal lattice image of the interface between the tunnel barrier layer and the first and/or the second ferromagnetic metal layer, a lattice-matched portion is made up of a plurality of sequential, continuously-connected lattice lines, and a lattice-mismatched portion is made up of a plurality of sequential, non-continuously-connected lattice lines and/or no lattice lines.