Abstract: The embodiments herein relate to a magnetic field feedback based spintronic microwave oscillator driven by DC current. The microwave oscillator works based on a magnetic tunnel junction structure connected to a feedback waveguide. Any fluctuation in the magnetization direction of free magnetization layer of MTJ drives an oscillating current through the feedback waveguide which in turn exerts an oscillating magnetic field on the free layer and amplifies the magnetization fluctuations. If the DC current passing through the MTJ is more than a critical value, continuous processing states of the magnetization are possible. The critical current is independent of the thickness and magnetization of the free layer. A MTJ can be driven into spontaneous oscillations with DC current and magnetic field feedback circuit and can act as a spintronic microwave oscillator.

Abstract: The embodiments herein relate to a magnetic field feedback based spintronic microwave oscillator driven by DC current. The microwave oscillator works based on a magnetic tunnel junction structure connected to a feedback waveguide. Any fluctuation in the magnetization direction of free magnetization layer of MTJ drives an oscillating current through the feedback waveguide which in turn exerts an oscillating magnetic field on the free layer and amplifies the magnetization fluctuations. If the DC current passing through the MTJ is more than a critical value, continuous processing states of the magnetization are possible. The critical current is independent of the thickness and magnetization of the free layer. A MTJ can be driven into spontaneous oscillations with DC current and magnetic field feedback circuit and can act as a spintronic microwave oscillator.

Abstract: A strip line integrated microwave generating element and a microwave detecting element comprises a signal electrode and a ground electrode. The element has a magnetic tunnel junction structure which includes a magnetization fixed layer, a MgO tunnel barrier layer, and a magnetization free layer. The magnetization free layer is 200 nm square or smaller in a cross-sectional area. The magnetization fixed layer is in contact with either one of the signal electrode and the ground electrode while the magnetization free layer of the element being in contact with the other. The element is smaller than the electrodes and mounted on a part of the signal electrode or the ground electrode. A MR ratio of the element is of 100% or more. A resistance value of the element is from 50? to 300?. The resistance of the element is matched with an impedance of the microwave transmission line.

Abstract: Microwave generating and detection portions of a electronic circuit is improved in efficiency and reduced in size. A microwave generating element A comprises a lower electrode 1, a layer 3 formed on the lower electrode 1 in an island shape, forming a magnetoresistance element, an insulator 7 formed on the lower electrode 1 in such a manner as to surround the layer 3 forming the magnetoresistance element, and an upper electrode 5 formed on the insulator 7 and the layer 3 forming the magnetoresistance element. The layer 3 forming the magnetoresistance element includes, in order from the side of the lower electrode 1, a magnetization fixed layer 3a, an intermediate layer 3b, and a magnetization free layer 3c. The magnetization free layer 3c, which is required to produce resonance oscillation based on a current, preferably is dimensioned to be equal to or smaller than 200 nm square in a cross-sectional area and on the order of 1 to 5 nm in film thickness, for example.