Magnetic tunnel junction, spintronics device using same, and method for manufacturing magnetic tunnel junction

A magnetic tunnel junction, comprising:

• a tunnel barrier layer provided between a first magnetic layer and a second magnetic layer,
• wherein the tunnel barrier layer is a crystal body made of a stacked structure of a first insulating layer and a second insulating layer, the crystal body is oriented,
• the first insulating layer is made of an oxide of Mg1-xXx (0≤x≤0.15), wherein X is at least one element selected from the group consisting of Al and Ti,
• a thickness of the first insulating layer is not less than 0.05 nm and not more than 1.2 nm,
• the second insulating layer is crystalline and made of an oxide of an alloy comprising at least two elements selected from the group consisting of Mg, Al, Zn, and Li,
• a sum of the thickness of the first insulating layer and a thickness of the second insulating layer is not less than 0.6 nm and not more than 3 nm, and
• both the first magnetic layer and the second magnetic layer are made of an alloy comprising B and at least one element selected from the group consisting of Co and Fe.