FERROMAGNETIC TUNNEL JUNCTION, MAGNETORESISTIVE EFFECT ELEMENT AND SPINTRONICS DEVICE IN WHICH SAID FERROMAGNETIC TUNNEL JUNCTION IS USED, AND METHOD OF MANUFACTURING FERROMAGNETIC TUNNEL JUNCTION

摘要

The object of the present invention is to attain an unconventionally high tunnel magnetoresistance (TMR) ratio by using a barrier layer made of an MgAl₂O₄ type insulator material with a spinel structure. The problem can be solved by a magnetic tunnel junction in which a barrier layer is made of a cubic nonmagnetic material having a spinel structure, and both of two ferromagnetic layers that are adjacently on and below the barrier layer are made of a Co₂FeAl Heusler alloy. Preferably, the nonmagnetic material is made of oxide of an Mg_1-xAl_x (0 x ≤ 1) alloy, and exhibits tunnel magnetoresistance of 250% or more and 34000% or less at a room temperature.