Dr. Alina Maria Deac
Phone: +49 351 260 - 3709

Research and Projects on Spintronics 


Helmholtz Young Investigator Group Dr. Alina Deac


A spin-polarized current flowing through a ferromagnet exerts a torque on the magnetization at the nanoscale, thereby providing means of manipulating it. In a nano-size magnet, spin-transfer torques can induce either magnetization reversal or steady-state precession. These phenomena have been proposed as write method for non-volatile magnetic memory devices and operating mechanism for tuneable radio-frequency nano-oscillators, respectively. Given their good scaling perspectives, spin-torque devices have recently been identified as one of the prime candidates for beyond Moore technologies. In particular, spin-torque devices based on MgO-based magnetic tunnel junctions show great promise for applications, although fundamental questions remain to be answered. Our research aims at unlocking the full potential of these devices with respect to Information-Communication Technology (ICT) by addressing critical outstanding challenges in understanding the fundamental physics of spin-transfer, and providing proof of concept for previously unexplored device structures and fabrication methods. 

We focus on three key objectives:

  • Establishing a unified understanding of spin-torque induced magnetization reversal, and identifying structures which combine thermal stability compatible with storage applications, reliably controlled writing and sufficiently low writing currents;
  • Creating tunable, zero-field spin-torque oscillators capable of simultaneously sustaining large output power (~µW) and narrow linewidth (~MHz), with a view on pushing their operation frequency towards higher ranges;
  • Developing the foundational science necessary to understand the potential of spin-transfer torques induced by thermal gradients to be functionalized for reducing power consumption, either on their own or in conjunction with spin polarized currents.

To achieve these objectives, new geometries are developed together with highly engineered structures using novel materials with both in-plane and perpendicular magnetic anisotropies, in collaboration with leading research groups around the world. Novel proton-irradiation techniques for locally modifying the conductive properties of oxides at the nanometer scale are explored, thereby allowing for the study of arrays of devices with densities inaccessible by state-of-the-art patterning methods.







   Dr. Alina Maria Deac (Group Leader)

   Dr. Ciaran Fowley (Postdoc)

   Dr. Oguz Yildirim (Postdoc)

   Yuriy Aleksandrov (PhD Student)

   Ewa Kowalska (PhD Student)

   Hamza Cansever (PhD Student)

   Hande Isim (ShK)

   Lakshmi Ramasubramanian (ShK)

   Eugene Clifford (Internship Student)



   Tiago Cordeiro (HZDR International Summer Student program member)

   Alexandra Titova (HZDR International Summer Student program member)

   Dr. David Ball (Postdoc)

   Dongseok Kim (Visiting PhD student of Prof. Kungwon Rhie)

   Dr. Volker Sluka (Postdoc)

   Prof. Kungwon Rhie (Guest Researcher)

   Dipl.-Ing. Kerstin Bernert (PhD student)

   Julia Gritsenko (HZDR International Summer Student program member)

   Dr. Huadong Gan (Guest Researcher)

   Wen Feng (HZDR International Summer Student program member, Masters Student)

   Sylvain Mathonnière (HZDR International Summer Student program member, Masters Student)

   Alexane Pointillon (Masters Student)


Open positions:

If you are interested in joining our group for your Bachelor, Masters or Diploma internship, or as a student lab assistent, please contact Dr. Alina Deac (






Relevant Publications:


"Large Emission Power over 2 µW with High Q Factor Obtained from Nanocontact Magnetic-Tunnel-Junction-Based Spin Torque Oscillator", Maehara, H., Kubota, H., Seki, S., Nishimura, K., Nagamine, Y., Tsunekawa, K., Fukushima, A., Deac, A.M., Ando, K., and Yuasa, S., Appl. Phys. Express 6, 113005 (2013). 

URL:  DOI:10.7567/APEX.6.113005


"Local modification of magnetic anisotropy and ion milling of Co/Pt multilayers using a He+ ion beam microscope", Fowley, C.,Diao, Z, Faulkner, C.C., Kally, J., Ackland, K., Behan, G., Zhang, H. Z., Deac, A.M., Coey, J.M.D., J. Phys. D: Appl. Phys. 46, 195501 (2013).

URL:  DOI:10.1088/0022-3727/46/19/195501

"Thermal creation of a spin current by Seebeck spin tunneling", Jansen, R., Le Breton, J. C., Deac, A.M., Saito, H., Yuasa, S.,

"Spin-transfer dynamics in spin valves with out-of-plane magnetized CoNi free layers", Rippard, W.H., Deac, A.M., Pufall, M.R., Shaw, J.M., Keller, M.W., Russek, S.E., Bauer, G.E.W., Serpico, C., Physical Review B - Condensed Matter and Materials Physics 81, 014426 (2010).

URL:  DOI:10.1103/PhysRevB.81.014426


"Bias-driven high-power microwave emission from MgO-based tunnel magnetoresistance devices",  Deac, A.M., Fukushima, A., Kubota, H., Maehara, H., Suzuki, Y., Yuasa, S., Nagamine, Y., Tsunekawa, K., Djayaprawira, D.D., Watanabe, N., Nature Physics 4, 803 - 809 (2008).

URL:  DOI:10.1038/nphys1036



Dr. Alina Maria Deac
Phone: +49 351 260 - 3709