1 / 12

Magnetoresistance in oxydized Ni nanocontacts

D. Jacob, J. Fernández-Rossier, J. J. Palacios. Department of Applied Physics, U. Alicante, 03690 SPAIN. Magnetoresistance in oxydized Ni nanocontacts. Ni. Ni. Ni. Ni. Oxygen. Small Magnetoresistance. Large Magnetoresistance >90%. D. Jacob, JFR, J. J. Palacios

shirin
Télécharger la présentation

Magnetoresistance in oxydized Ni nanocontacts

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. D. Jacob, J. Fernández-Rossier, J. J. Palacios Department of Applied Physics, U. Alicante, 03690 SPAIN Magnetoresistance in oxydized Ni nanocontacts Ni Ni Ni Ni Oxygen Small Magnetoresistance Large Magnetoresistance >90% D. Jacob, JFR, J. J. Palacios PRB 71, R220403 (2005) D. Jacob, JFR, J. J. Palacios Cond-mat, 0603359 A single atom can make a difference www.ua.es/personal/jfrossier/ V22.00002

  2. Motivation I: MR EXPERIMENT:Small BMR in Ni80Fe20 K. Bolotin et al. Nano Lett.,6(1), 123, (06) D. Jacob, JFR; J. J. Palacios PRB71, R220403 (2005) THEORY: Small BMR in PURE Ni nanocontacts

  3. Ni Ni Oxigen Motivation II: Motivation III: Probing Ni-O-Ni chemical bond Bulk NiO=AF Mott Insulator

  4. Electronic Structure calculation Ni Ni Oxygen Tight Binding B3LYP Free Bands • Parametrization 3D • Charge neutrality • Bulk NiO: • AF OK • Insulator OK • GAP Ok • Magnetic Moment OK • No Self Interaction: OK LDA • NiO: FM, no gap, no Mott Hubbard • Self Interaction

  5. Ni Ni Oxigen Electronic Structure calculation Tight Binding B3LYP Free Bands • Parametrization 3D • Charge neutrality • Bulk NiO: • AF OK • Insulator OK • GAP Ok • Magnetic Moment OK • No Self Interaction: OK LDA • NiO: FM, no gap, no Mott Hubbard • Self Interaction

  6. Electronic Structure: Infinite chains CRYSTAL03 B3LYP, NiO FM chain FERROMAGNETIC HALF METAL 2 Doubly degenerate E1 band Ni(+)O(-)

  7. Electronic Structure: Infinite chains CRYSTAL03 B3LYP, NiO AF chain ANTIFERROMAGNETIC INSULATING Ni(+)O(-)

  8.  Ni Ni Oxigen Electronic structure: nanocontact • Infinite system without translational invariance • Cluster Embeddedcalculation • Cluster in DFT aprox, LCAO, GAUSSIAN03 • Leads: semiempirical TB, Bethe lattice

  9. Nanocontacts: Single Oxygen Bridge High MR

  10. Electronic Structure: Infinite chains FERROMAGNETIC INSULATING WARNING: Small MR

  11. Insulating SINGLE ATOM SPIN VALVE Ni Ni Ni Conducting

  12. Conclusions • A single atom can make a difference: Ni-O-Ni can have large MR • A single atom can makes a difference:SINGLE ATOM SPIN VALVE • Atomic sized contacts: PROBING TM-O-TM chemical bonding www.ua.es/personal/jfrossier Jfrossier@ua.es

More Related