Microwave oscillations of the magnetization around its equilibrium are the natural dynamical response to external perturbations (e.g. thermal fluctuations, microwave fields). This offer the promise for a new class of microwave devices, benefiting from their small foot-print, their ability to be controlled electrically, and their integrability with CMOS technology. Identified devices include local oscillators, microwave filters, detectors, and non-reciprocal devices. Understanding the dynamics of these nano-objects, applying general concepts of microwave oscillator techniques and defining from this novel microwave applications is the major aim of this activity.
Spin Transfer Torque Oscillators
We are realizing and studying microwave emitting sources based on the magnetization precession, mainly in the shape of nanopillars made out of magnetic heterostrucures. This offer the possibility to build new devices for telecommunication in the Ghz range.
Magnons are the quasi-particles associated to the collective excitations of spins. Mode engineering and transfer of angular momentum by magnonics current are some of our key ongoing research activities.
- Chandrasekhar Murapaka
- Alumni : A. Ruiz Calafora, K. Jaimes Merazzo, K. Garcia Hernandez
- Kyota Watanabe (GP-Spin program)
- Matthieu Favre
- Jérôme Hem
- Anike Purbawati
- W.E. Bailey – Columbia University (2009, 2010, 2011, 2012), A. N. Slavin – Oakland University (2012, 2013), V. Naletov (2016)
- Leti (Grenoble)
- Unité Mixte CNRS/Thale (Palaiseau),
- Service de l’etat condense-CEA (Saclay)
- Univ. Munster (Germany)
- INL (Portugal)
- University of Münster (Germany)
- Oakland University (United States of America)
- HOW TO INCREASE THE OUTPUT POWER : SPIN VALVES VS. TUNNEL JUNCTIONS ! (July 02nd, 2015)
What are the requirements ? Integration of STOs into conventional RF circuitry means that the STO has to meet certain specifications. The most important are output power and phasenoise. In this section we consider only ...
- HOW TO MAXIMIZE THE PRECESSION AMPLITUDE USING A PERPENDICULAR POLARIZER ? (July 02nd, 2015)
How to stabilize an ascillation around the energy maximum ? Why a perpendicular polarizer ? First experiments of spin torque driven excitations using an in-plane magnetized polarizer (in a standard spin valve structures) showed ...
- HOW TO INCREASE THE OUTPUT POWER : HIGH IMPEDANCE AMPLIFICATION ! (July 02nd, 2015)
What are the requirements? Integration of STOs into conventional RF circuitry means that the STO has to deliver 0dBm to drive for instance RF blocks such as a mixer. Using magnetic tunnel junction devices we have ...
- WHITE PAPERS / MAJOR PUBLICATIONS (July 02nd, 2015)
WHITE PAPERS / MAJOR PUBLICATIONS
- IMPEDANCE MATCHING (July 02nd, 2015)
Increasing Output Power by impedance matching Description Impedance mismatch between the STNO device (for MTJs 100 – 1000 Ohm) and standard RF circuitry (at 50 Ohm) leads to a reduction of the output power of 10 dB. ...