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Dr Dirk Backes

Dr Dirk Backes

Postdoctoral research associate (PDRA)

Room 334
Office Phone: 01223 764178

Biography:

I was a research assistant at the Paul Scherrer Institute in Switzerland, where I investigated current-induced domain wall motion in nanomagnetic devices. After receiving a doctorate in physics (Dr. rer. nat.) from the University of Konstanz in Germany, I worked as a postdoctoral associate in the group of Prof. Andrew Kent at New York University. There I developed magnetic multilayers for spin-transfer torque random access memory (STT-MRAM) devices and developed a fabrication process for spin torque nano oscillators (STNO). As of March 2014, I am a postdoctoral research associate in the Semiconductor Physics group at the University of Cambridge. I am studying transport in the presence of disorder in mesoscopic 2-dimensional electron systems based on GaAs/AlGaAs-heterostructures. This work is carried out in collaboration with Prof. Mike Pepper from UCL in London.

Research Interests

My current research interest is in topological insulators. For the future, l would like to harvest the unique properties of topological transport for spintronic applications and to demonstrate functional hybrid topological insulator/spintronic devices.

Key Publications

36.

‘Metal-like’ transport in high-resistance, high aspect ratio two-dimensional electron gases
D. Backes, R. Hall, M. Pepper, H. Beere, D. Ritchie, V. Narajan
Journal of Physics: Condens. Matter 28, 01LT01 (2016); arXiv 1510.00236

35.

Observation of geometry-dependent conductivity in two-dimensional electron gases
D. Backes, R. Hall, M. Pepper, H. Beere, D. Ritchie, V. Narajan
Phys. Rev. B 92, 235427 (2015); arXiv 1505.03444

34.

Direct observation of large amplitude spin excitations localized in a spin-transfer nanocontact
D. Backes, F. Macia, S. Bonetti, R. Kukreja, H. Ohldag, A. D. Kent
Phys. Rev. Lett. 115, 127205 (2015); arXiv 1504.00488

33.

Direct observation of a spin-wave soliton with a p-wave character
S. Bonetti, R. Kukreja, J. Katine, F. Macia, D. Backes, A. D. Kent, J. Stoehr, H. Ohldag, H. A. Duerr
Nature Comm. 6:8889 (2015); arXiv 1504.00144

32.

Observation of droplet soliton drift resonances in a spin-transfer-torque nanocontact to a ferromagnetic thin film
S. Lendinez, N. Statuto, D. Backes, A.D. Kent, and F. Macia
Phys. Rev. B 92, 174426 (2015); arXiv 1507.08218

31.

X-ray detection of transient spin accumulation on Cu atoms near a Cu/Co interface
R. Kukreja, S. Bonetti, Z. Chen, D. Backes, Y. Acremann, J. Katine, A. D. Kent, H. A. Duerr, H. Ohldag, J. Stoehr
Phys. Rev. Lett. 115, 096601 (2015); arXiv 1503.07275

30.

Determining energy relaxation length scales in two-dimensional electron gases
J. Billiald, D. Backes, J. Koenig, I. Farrer, D. Ritchie, V. Narayan
Appl. Phys. Lett. 107, 022104 (2015); arXiv 1504.06524

29.

Stable magnetic droplet solitons in spin-transfer nanocontacts
F. Macia, D. Backes, A. D. Kent
Nature Nanotech. 9, 992 (2014); arXiv 1408.1902

28.

Spin-transfer switching of orthogonal spin-valve devices at cryogenic temperatures
L. Ye, D. B. Gopman, L. Rehm, D. Backes, G. Wolf, T. Ohki, A. F. Kirichenko,  I. V. Vernik, O. A. Mukhanov, A. D. Kent
J. Appl. Phys. 115, 17C725 (2014)

27.

Characterization of interlayer interactions in magnetic random access memory layer stacks using ferromagnetic resonance
D. Backes, D. Bedau, H. Liu, J. Langer, A. D. Kent
J. Appl. Phys. 111, 07C721 (2012)

26.

Precessional reversal in orthogonal spin transfer magnetic random access memory devices
H. Liu, D. Bedau, D. Backes, J. A. Katine, A. D. Kent
Appl. Phys. Lett. 101, 032403 (2012)

25.

Formation of magnetic domains and domain walls in epitaxial Fe3O4(100) elements
M. Fonin, C. Hartung, U. Rüdiger, D. Backes, L. Heyderman, F. Nolting, A. Fraile Rodríguez, M. Kläui
J. Appl. Phys. 109, 07D315 (2011) (invited)

24.

Domain wall velocity measurement in permalloy nanowires with X-ray magnetic circular dichroism imaging and single shot Kerr microscopy
T.A. Moore, M. Kläui, L. Heyne, P. Möhrke, D. Backes, J. Rhensius, U. Rüdiger, L.J. Heyderman, T.O. Mentes, M.Á. Niño, A. Locatelli, A. Potenza, H. Marchetto, S. Cavill, S.S. Dhesi
J. Magn. Magn. Mat. 322, 1347 (2010)

23.

Domain-Wall Depinning Assisted by Pure Spin Currents
D. Ilgaz, J. Nievendick, L. Heyne, D. Backes, J. Rhensius, T. A. Moore, M. A. Niño, A. Locatelli, T. O. Mentes, A. v. Schmidsfeld, A. v. Bieren, S. Krzyk, L. J. Heyderman, M. Kläui
Phys. Rev. Lett. 105, 076601 (2010)

22.

Imaging of domain wall inertia in Permalloy half-ring nanowires by time-resolved photoemission electron microscopy
J. Rhensius, L. Heyne, D. Backes, S. Krzyk, L. J. Heyderman, L. Joly, F. Nolting, M. Kläui
Phys. Rev. Lett. 104, 067201 (2010)

21.

Magnetic-field-induced domain-wall motion in permalloy nanowires with modified Gilbert damping
T. A. Moore, P. Möhrke, L. Heyne, A. Kaldun, M. Kläui, D. Backes, J. Rhensius, L. J. Heyderman, J.-U. Thiele, G. Woltersdorf, A. Fraile Rodríguez, F. Nolting, T. O. Mentes, M. A. Niño, A. Locatelli, A. Potenza, H. Marchetto, S. Cavill, S. S. Dhesi
Phys. Rev. B 82, 094445 (2010)

20.

Ultrafast switching in magnetic tunnel junction based orthogonal spin transfer devices
H. Liu, D. Bedau, D. Backes, J. A. Katine, J. Langer, A. D. Kent
Appl. Phys. Lett. 97, 242510 (2010)
 APL Author’s Pick

19.

Concepts for Domain Wall Motion in Nanoscale Ferromagnetic Elements due to Spin Torque and in Particular Oersted Fields
M. Kläui, D. Ilgaz, L. Heyne, J.-S. Kim, O. Boulle, C. Schieback, F. Zinser, S. Krzyk, M. Fonin, U. Rüdiger, D. Backes, L. J. Heyderman, T. O. Mentes, A. Locatelli
J. Mag. 14, 53 (2009)

18.

Geometry-dependent scaling of critical current densities for current-induced domain wall motion and transformations
L. Heyne, J. Rhensius, Y.-J. Cho, D. Bedau, S. Krzyk, C. Dette, H. S. Körner, J. Fischer, M. Laufenberg, D. Backes, L. J. Heyderman, L. Joly, F. Nolting, G. Tatara, H. Kohno, S. Seo, U. Rüdiger, M. Kläui
Phys. Rev. B 80, 184405 (2009)

17.

Scaling of spin relaxation and angular momentum dissipation in permalloy nanowires
T. A. Moore, M. Kläui, L. Heyne, P. Möhrke, D. Backes, J. Rhensius,
U. Rüdiger, L. J. Heyderman, J.-U. Thiele, G. Woltersdorf, C. H. Back, A. Fraile Rodríguez, F. Nolting, T. O. Mentes, M. Á. Niño, A. Locatelli, A. Potenza, H. Marchetto, S. Cavill, S. S. Dhesi
Phys. Rev. B 80, 132403 (2009)

16.

Direct imaging of current-induced domain wall motion in CoFeB structures
L. Heyne, M. Kläui, D. Backes, P. Möhrke, T. A. Moore, J. G. Kimling, O. Boulle, U. Rüdiger, L. J. Heyderman, A. Fraile Rodríguez, F. Nolting, K. Kirsch, R. Mattheis
J. Appl. Phys. 103, 07D928 (2008)

15.

Quantitative determination of vortex core dimensions in head-to-head domain walls using off-axis electron holography
F. Junginger, M. Kläui, D. Backes, S. Krzyk, U. Rüdiger, T. Kasama, R. E. Dunin-Borkowski, J.-M. Feinberg, R. J. Harrison, L. J. Heyderman
Appl. Phys. Lett. 92, 112502 (2008)

14.

Relationship between nonadiabaticity and damping in Permalloy studied by current induced spin structure transformations
L. Heyne, M. Kläui, D. Backes, T. A. Moore, S. Krzyk, U. Rüdiger, L. J. Heyderman, A. Fraile Rodríguez, F. Nolting, T. O. Mentes, M. Á. Niño, A. Locatelli, K. Kirsch, R. Mattheis
Phys. Rev. Lett. 100, 066603 (2008)

13.

Selective domain wall depinning by localized Oersted fields and Joule heating
D. Ilgaz, M. Kläui, L. Heyne, O. Boulle, F. Zinser, S. Krzyk, M. Fonin, U. Rüdiger, D. Backes, L. Heyderman
Appl. Phys. Lett. 93, 132503 (2008)

12.

Single shot Kerr magnetometer for observing real-time domain wall motion in permalloy nanowires
P. Möhrke, T. A. Moore, M. Kläui, J. Boneberg, D. Backes, S. Krzyk, L. J. Heyderman, P. Leiderer, U. Rüdiger
J. Phys. D: Appl. Phys. 41 164009 (2008)

11.

Domain walls, domain wall transformations and structural changes in Permalloy nanowires when subjected to current pulses
E.-M. Hempe, M. Kläui, T. Kasama, D. Backes, F. Junginger, S. Krzyk, L. J. Heyderman, R. Dunin-Borkowski, U. Rüdiger
phys. stat. sol. (a) 204, 3922 (2007)

10.

Ferromagnetic nanorings
C. A. F. Vaz, T. J. Hayward, J. Llandro, F. Schackert, D. Morecroft,
J. A. C. Bland, M. Kläui, M. Laufenberg, D. Backes, U. Rüdiger, F. J. Castaño, C. A. Ross, L. J. Heyderman, F. Nolting, A. Locatelli, G. Faini, S. Cherifi, W. Wernsdorfer
J. Phys.: Condens. Matter 19, 255207 (2007)

9.

Spin torque and heating effects in current-induced domain wall motion probed by transmission electron microscopy
F. Junginger, M. Kläui, D. Backes, U. Rüdiger, T. Kasama, R. E. Dunin-Borkowski, L. J. Heyderman, C. A. F. Vaz, J. A. C. Bland
Appl. Phys. Lett. 90, 132506 (2007)

8.

Transverse Domain Walls in Nanoconstrictions
D. Backes, C. Schieback, M. Kläui, F. Junginger, H. Ehrke, P. Nielaba, U. Rüdiger, L. J. Heyderman, C. S. Chen, T. Kasama, R. E. Dunin-Borkowski, C.A.F. Vaz, J.A.C. Bland
Appl. Phys. Lett. 91, 112502 (2007)

7.

Current-induced vortex nucleation and annihilation in vortex domain walls
M. Kläui, M. Laufenberg, L. Heyne, D. Backes, U. Rüdiger, C. A. F. Vaz, J. A. C. Bland, L. J. Heyderman, S. Cherifi, A. Locatelli, T. O. Mentes, L. Aballe
Appl. Phys. Lett. 88, 232507 (2006)

6.

Fabrication of curved-line nanostructures on membranes for transmission electron microscopy investigations of domain walls
D. Backes, L. J. Heyderman, C. David, R. Schäublin, M. Kläui, H. Ehrke, U.Rüdiger, C. A. F. Vaz, J. A. C. Bland, T. Kasama, R. E. Dunin-Borkowski
Microelect. Eng. 83, 1726 (2006)
Young Authors Award MNE 2005

5.

Magnetization reversal in cobalt antidot arrays
L. J. Heyderman, F. Nolting, D. Backes, S. Czekaj, L. Lopez-Diaz, M. Kläui, U. Rüdiger, C. A. F. Vaz, J. A. C. Bland, R. J. Matelon, U. G. Volkmann, P. Fischer
Phys. Rev. B 73, 214429 (2006)

4.

Observation of thermally activated domain wall transformations
M. Laufenberg, D. Backes, W. Bührer, D. Bedau, M. Kläui, U. Rüdiger, C. A. F. Vaz, J. A. C. Bland, L. J. Heyderman, F. Nolting, S. Cherifi, A. Locatelli, R. Belkhou, S. Heun, E. Bauer
Appl. Phys. Lett. 88, 052507 (2006)

3.

Quantitative determination of domain wall coupling energetics
M. Laufenberg, D. Bedau, H. Ehrke, M. Kläui, U. Rüdiger, D. Backes, L. J. Heyderman, F. Nolting, C. A. F. Vaz, J. A. C. Bland, T. Kasama, R. E. Dunin-Borkowski, S. Cherifi, A. Locatelli, S. Heun
Appl. Phys. Lett. 88, 212510 (2006)

2.

Spatially resolved dynamic Eigenmode spectrum of Co rings
I. Neudecker, M. Kläui, K. Perzlmaier, D. Backes, L. J. Heyderman, C. A. F. Vaz, J. A. C. Bland, U. Rüdiger, C. H. Back
Phys. Rev. Lett. 96, 057207 (2006)

1.

Direct observation of domain-wall pinning at nanoscale constrictions
M. Kläui, H. Ehrke, U. Rüdiger, T. Kasama, R. E. Dunin-Borkowski, D. Backes, L. J. Heyderman, C. A. F. Vaz, J. A. C. Bland, G. Faini, E. Cambril, W. Wernsdorfer
Appl. Phys. Lett. 87, 102509 (2005)