Speaker:
Dirk Sander
Institution:
Max Planck Inst.
Date:
Thursday, August 6, 2015
Time:
4:00 pm
Location:
NS2 1201
ABSTRACT:
Spin-polarized scanning tunneling microscopy at low temperature (8 K) and in high magnetic fields (6 T) is a powerful technique to investigate magnetic properties of individual nanoscale objects ranging in size form single atoms to several thousand atoms [1]. I focus on the magnetization reversal [2] and the spin-dependent electronic properties of bilayer Co [3], Fe-decorated Co and Fe islands [4] on Cu(111). We find a novel noncollinear, helical magnetic order in the Fe islands, which is identified by a magnetic stripe contrast with a period of 1.28 nm. The high spatial resolution of the scanning tunneling spectroscopy reveals the significance of structural and electronic relaxation [5] for the magnetic anisotropy and the spin-dependent transport properties [6] of single islands. In an outlook I present first results from our new STM, which operates at 0.3 K in a vector magnetic field, on superconductivity of Pb monolayers and on the proximity effect [7].
[1] H. Oka, O. Brovko, M. Corbetta, V. Stepanyuk, D. Sander, J. Kirschner,
Rev. Mod. Phys. 86 (2014), 1127.
[2] S. Ouazi, G. Rodary, S. Wedekind, H. Oka, D. Sander, J. Kirschner,
Phys. Rev. Lett. 108 (2012) 107206.
[3] H. Oka, P. Ignatiev, S. Wedekind, G. Rodary, L. Niebergall, V. Stepanyuk, D. Sander, J. Kirschner, Science 327(2010) 843.
[4] S. Phark, J. Fischer, M. Corbetta, D. Sander, K. Nakamura, J. Kirschner,
Nat. Commun. 5:5183 doi: 10.1038/ncomms6183 (2014).
Nat. Commun. 5:5183 doi: 10.1038/ncomms6183 (2014).
[5] O. Brovko, D. Bazhanov, H. Meyerheim, D. Sander, V. Stepanyuk, J. Kirschner,
Surface Science Reports 69 (2014) 159.
[6] H. Oka, K. Tao, S. Wedekind, G. Rodary, V. Stepanyuk, D. Sander, J. Kirschner,
Phys. Rev. Lett. 107 (2011) 187201.
[7] M. Caminale, A. Leon-Vanegas, A. Stepniak, H. Oka, D. Sander, J. Kirschner, Phys. Rev. B 90 (2014) 220507(R).
Host:
John Hemminger