RF Devices

 

Team Leader 

 

Thematic overview

Microwave oscillations of the magnetization around its equilibrium are a natural response to external perturbations (e.g. thermal fluctuations, microwave fields). Inducing these oscillations using spin momentum transfer (by injecting a spin polarized charge current) results in a rich magnetization dynamics in nanostructured spintronics devices. Understanding of these spin torque driven magnetization oscillations, applying general concepts of microwave oscillator techniques and defining from this novel microwave applications is the major aim of this activity.

Questions to be addressed

Understanding the interaction of spin polarized currents with the local magnetization Development of materials and magneto-resistive stacks to tailor microwave performances Understanding of excitation modes and their frequency tuning characteristics for different magneto-resistive device configurations Understanding the non-linear magnetization dynamics under spin transfer torque Understanding of the origin of linewidth broadening Enhancing output power Measuring and reducing phase noise Optimizing signal treatment functions Addressing system and integration issues for RF circuits

Projects

  • Spin pumping and spin absorption
  • Development of magnetic tunnel junctions of low RA and high TMR
  • Spin torque driven magnetization dynamics of a perpendicular polarizer and SAFs
  • Impedance matching for increasing output power
  • Linewidth broadening and phase noise (experimental techniques, analysis and extraction of non-linear parameters)
  • Signal treatment functions (Synchronization + Modulation of STNOs) RF systems based on STNOs microwave generation

Partners

  • LETI/DCOS & LETI /DACLE
  • CEA/INAC/SP2M/NM
  • CNRS/Thales, Palaiseau
  • CEA/Saclay
  • CNRS/XLIM/Brive
  • HITACHI GST, San José, USA
  • OAKLAND University, Michigan, USA
  • COLUMBIA University, New York, USA
  • University Autonomous Madrid, Sapin
  • F. Wilhelm, A. Rogalev, ESRF - Grenoble
  • KOREA University, Seoul, Korea
  • University of TRANSILVANIA, Brasov, Roumania
  • TU Dresden, Germany

Team

Staff: Ursula Ebels (team leader Spintec), Marie Claire Cyrille (team leader CEA/LETI), Liliana Prejbeanu (Simulation), Daria Gusakova (Simulation), Stephane Auffret (Materials), Bernard Rodmacq (Materials), Bernard Dieny

PHD students: Michael Quinsat, Abhijit Ghosh, Christophe Dieudonné, Elmer Monteblanco

Postdocs: Felipe Garcia, Jiafeng Feng, Alex Jenkins

Guests: Olivier Klein-CEA Saclay (2012, 2013), WE Bailey-Columbia University (2009, 2010, 2011, 2012), A N Slavin-Oakland University (2012, 2013), Seo-Won Lee-Korea University, Seoul (PhD exchange student 2011), Ioana Firastrau-Transilvania University, Brasov, Roumania (2010, 2011, 2012)