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Anisotropic Physical Properties of Decagonal Quasicrystals Janez Dolinšek Jožef Stefan Institute, University of Ljubljana, Slovenia. Slovenia. Ljubljana. area: 20.000 km 2 population: 2 million. Adriatic sea. Lipizaner horses. Julian Alps. Lake Bled.
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Anisotropic Physical Properties of Decagonal Quasicrystals Janez Dolinšek Jožef Stefan Institute, University of Ljubljana, Slovenia
Slovenia Ljubljana area:20.000 km2 population: 2 million Adriatic sea Lipizaner horses Julian Alps Lake Bled
“Jožef Stefan” Institute, Ljubljana, Slovenia staff: 850 revenues (2012): 52 MEur physics chemistry biology
Structure of decagonal quasicrystals Geometrical description: periodic stacking of quasiperiodic atomic layers quasiperiodic atomic layers periodic 10-fold direction P
Investigated phase Decagonalquasicrystald-Al-Co-Ni: - symmetry: decagonal - chemicalcomposition (at. %): Al70Co10Ni20 2 atomiclayerswithin one periodicunitof 0.4 nmalong105axis 5
Physical properties investigated: • electrical resistivityρ(T) • magnetism χ(T), M(H) • thermoelectric power S(T) • - Hall coefficient RH(T) • thermal conductivity κ(T)
Anisotropic physical properties of d-Al-Co-Ni measurements performed along four crystallographic directions (three “in-plane” and the stacking “10-fold” direction) P ... stacking direction P
d-Al-Co-Ni: samples preparation P P P. Gille, G. Meisterernst, N. Faber, J. Crystal Growth 275, 224 (2005) 8
Symmetry analysis General form of a tensorial physical property (2nd rank tensor) for a decagonal point group: P 9
d-Al70Co10Ni20: symmetry analysis by 27Al NMR 27Al NMR spectrum central line central line satellites M. Bobnar et al., Phys. Rev. B 85, 024205 (2012) 10
d-Al70Co10Ni20: orientation-dependent 27Al NMR satellite intensity 12
d-Al70Co10Ni20: orientation-dependent 27Al NMR satellite intensity 13
d-Al70Co10Ni20: electrical resistivity T-dependent resistivity in the Q plane P P Theory: Model of slow charge carriers G. Trambly de Laissardièreet al., Phys. Rev. Lett. 97, 026601 (2006)
d-Al70Co10Ni20 :Hall coefficient P M. Bobnar et al., Phys. Rev. B 85, 024205 (2012) 15
: d-Al70Co10Ni20 : thermal conductivity P M. Bobnar et al., Phys. Rev. B 85, 024205 (2012) 16
Magnetization vs. magnetic field and magnetic susceptibility Stronger diamagnetism for the field along 10-fold axis: atomic rings in the Q plane form diamagnetic circular current loops P P W. Steurer et al., Acta Cryst. B 49, 661 (1993)
Conclusions • electrical, thermal and magnetic properties of d-Al-Co-Ni decagonal quasicrystal are highly anisotropic; • stacking direction is the most conducting direction for the electricity and heat; • origin of anisotropy is the anisotropic stacked-layer atomic structure.
Coworkers and cooperation J. Stefan Institute, Ljubljana Stane Vrtnik Matej Bobnar Zvonko Jagličić Institute of Physics, Zagreb Ana Smontara Ludwig-Maximilian University, Munich Peter Gille