Low resistance magnetic tunnel junction device with bilayer or multilayer tunnel barrier

A magnetic tunnel junction read sensor comprising:

• a first electrical lead;
• a fixed ferromagnetic layer having a magnetic moment that is fixed in a preferred direction in the presence of an applied magnetic field in the range of interest;
• an antiferromagnetic layer between the first lead and the fixed ferromagnetic layer for pinning the magnetic moment of the fixed ferromagnetic layer in its fixed direction;
• a free ferromagnetic layer whose magnetic moment is free to rotate in the presence of the applied magnetic field in the range of interest;
• a bilayer insulating tunnel barrier layer located between the fixed and free ferromagnetic layers, the bilayer consisting of a first layer consisting essentially of aluminum nitride on and in contact with the fixed ferromagnetic layer and a second layer consisting essentially of aluminum oxide located between and in contact with the aluminum nitride layer and the free ferromagnetic layer;
• and
• a second electrical lead on the free ferromagnetic layer;
• and
• wherein the magnetic tunnel junction read sensor has a resistance-area value in the range of approximately 0.1 to 100 Ω(μm)2.