Spin-valve or tunnel-junction radio-frequency oscillator, process for adjusting the frequency of such an oscillator and network consisting of a plurality of such oscillators

A radio-frequency oscillator incorporating a magnetoresistive device within which an electron current is able to flow, said device comprising a stack of layers comprising:

• a magnetic trapped layer, a magnetization of which is of substantially fixed direction;
• a magnetic free layer;
• and
• a non-magnetic intermediate layer interposed between the free layer and the trapped layer;
• the oscillator also comprising means capable of making an electron current flow in said layers constituting said stack and in a direction perpendicular to a plane which contains said layers,
• wherein at least the free layer is devoid of any material at a center thereof;
• and,
• wherein the means capable of making an electron current flow generates a current flowing through the stack of said layers having a density capable of generating a magnetization in said free layer in a micromagnetic configuration in the shape of a skewed vortex flowing in said free layer around the center of said free layer.