Commissariat a L'energie Atomique Et Aux Energies Alternatives

Centre National De La Recherche Scientifique

Commissariat a L'energie Atomique

Institut Polytechnique De Grenoble

Le Commissariat a L'energie Atomique Et Aux Energies Altenatives

Ursula Ebels

Marie-Claire Cyrille

Bernard Dieny

Dimitri Houssameddine

Bertrand Delaet

Jean-Philippe Michel

Michaël Quinsat

Ricardo Sousa

Patrick Villard

Mykhailo Zarudniev

Michaël Pelissier

Dominique Lestelle

Marie Claire Cyrille

Liliana Prejbeanu

Eric Gautier

Cristian Papusoi

Liliana Buda-Prejbeanu

Ioana Firastrau

Marie- Claire Cyrille

The invention relates to a radiofrequency oscillator which incorporates: a spin-polarized electric current magnetoresistive device (), a terminal () for controlling the frequency or amplitude of the oscillating signal, a servo loop () connected between the output terminal and the control terminal for applying a control signal to the control terminal in order to slave a characteristic of the oscillating signal to a reference value, the servo loop () comprising: a sensor () of the amplitude of the oscillating signal oscillations, and a comparator () capable of generating the control signal according to the measured amplitude and the reference value.

Magnetoresistive radiofrequency oscillator and method for generating an oscillating signal

The invention relates to a radiofrequency oscillator which incorporates: a spin-polarized electric current magnetoresistive device () for generating an oscillating signal at an oscillation frequency on an output terminal (), and a terminal () for controlling the frequency or amplitude of the oscillating signal, and a feedback loop () comprising an amplifier () provided with: an input connected to the output terminal () of the magnetoresistive device () so as to amplify the portion of an oscillating signal detected at the output terminal, and an output connected to the control terminal () so as to inject onto said control terminal the amplified portion of the oscillating signal which is phase-related to the oscillating signal generated at the output terminal.

A radiofrequency oscillator comprises: a free layer (), a current injector () for injecting spin-polarized current into the free layer, this injector having a spin-polarized current injection face () directly in contact with the free layer, a magnetoresistive contact () having a measurement face () directly in contact with the free layer, in order to form, in combination with the free layer, a tunnel junction for measuring the precession of the magnetization of the free layer, a conducting pad () directly in contact with the free layer in order to make an electrical current flow through the injector without passing through the magnetoresistive contact. At least part of the measurement face () and part of the injection face () are placed facing each other on each side of the free layer ().

Magnetoresistive radiofrequency oscillator

A demodulator of an FM signal modulated about a carrier frequency with a modulation frequency has an RF oscillator configured to be synchronized, under identical conditions of operation, with oscillations at first and second frequencies used in the FM signal to encode respective pieces of information. The oscillator has a magnetoresistive device; and a low-pass filter connected to an output electrode of the magnetoresistive device to filter an oscillating signal, generated by the oscillator and to a rendering terminal to provide, as a demodulated electrical signal, the filtered signal, the cut-off frequency fat &#x2212;3 dB of this filter being strictly lower than the frequency and higher than the modulation frequency.

Demodulator of a frequency-modulated electrical signal

An oscillation detector having an RF oscillator configured to be synchronized with a first frequency and a comparator for distinguishing the synchronized state from the non-synchronized state of the radiofrequency oscillator on the basis of an oscillating signal produced by the radiofrequency oscillator and indicating the presence of oscillations in a frequency band around the first frequency in response to identifying the synchronized state and, in alternation, indicating the absence of oscillations in this frequency band otherwise.

Oscillation detector

A radio-frequency oscillator incorporates a magnetoresistive device within which an electron current is able to flow. The device includes a stack including: a magnetic trapped layer, the 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 includes a mechanism capable of making an electron current flow in the layers constituting the stack and in a direction perpendicular to the plane which contains the layers. At least the free layer is devoid of any material at its center. The electron current density flowing through the stack is capable of generating a magnetization in the free layer in a micromagnetic configuration in the shape of a skewed vortex flowing in the free layer around the center of the free layer.

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

The present invention relates to a method of fabricating a nanostructure, comprising the following steps: prestructuring a substrate () adapted to receive the nanostructure to form a nanorelief () on the substrate, the nanorelief having flanks () extending from a bottom () of the substrate and a top face () extending from said flanks, and then depositing on the substrate pre-structured in this way a single layer or multilayer coating intended to form the nanostructure; and further comprising: adding to the prestructured substrate or to the coating a separation layer adapted to enable separation of the coating and the substrate by external action of mechanical, thermomechanical or vibratory type; and exerting this external action on the substrate and/or the coating to recover selectively a top portion of the coating by separating it from the top face of the nanorelief so that this top portion constitutes some or all of the nanostructure.

Method of fabricating a nanostructure on a pre-etched substrate

A magnetic device includes a magnetic reference layer with a fixed magnetization direction located either in the plane of the layer or perpendicular to the plane of the layer, a magnetic storage layer with a variable magnetization direction, a non-magnetic spacer separating the reference layer and the storage layer and a magnetic spin polarizing layer with a magnetization perpendicular to that of the reference layer, and located out of the plane of the spin polarizing layer if the magnetization of the reference layer is directed in the plane of the reference layer or in the plane of the spin polarizing layer if the magnetization of the reference layer is directed perpendicular to the plane of the reference layer. The spin transfer coefficient between the reference layer and the storage layer is higher than the spin transfer coefficient between the spin polarizing layer and the storage layer.

Spin polarised magnetic device

The invention relates to a method of operating a spin-transfer torque structure to generate voltage oscillations, said structure comprising a first layer of magnetic material having a fixed magnetization vector, a spacer of non magnetic material and a second layer of magnetic material having a free magnetization vector. The method includes the application of a current (j) through said structure and a magnetic field (H) in the plane of the second layer. It makes use of a region of bistability and hysteretic behaviour to trigger and stop the voltage oscillations.

Growing community of inventors

Grenoble, France

Ursula Ebels