Download
slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Coupling Single Molecule Magnets to Ferromagnetic Substrates PowerPoint Presentation
Download Presentation
Coupling Single Molecule Magnets to Ferromagnetic Substrates

Coupling Single Molecule Magnets to Ferromagnetic Substrates

128 Vues Download Presentation
Télécharger la présentation

Coupling Single Molecule Magnets to Ferromagnetic Substrates

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Coupling Single Molecule Magnets to Ferromagnetic Substrates

  2. TbPc2 (Terbium-Phthalocyanino) SMM • Double Decker • Structure • Electronic config. • of Tb: [Xe]4f96s2 Phthalocyanine C32H18N8

  3. Experimental Setup • Easy axis of Ni: • Out of Plane (OP) of Ni film • and collinear with TbPc2 axis. • OP axis is created by adding • 13 monolayers of Ni on • Cu(100) surface. • Easy axis of Ni: • In Plane (IP) of Ni film and • perpendicular to TbPc2 axis. • IP axis is created by adding • 6 monolayers of Ni on • Ag(100) surface. A magnetic field B was applied parallel to x-ray direction at normal (=0o ) and grazing (=70o ) incidence to measure OP and IP magnetization.

  4. X-ray Magnetic Circular Dichcroism (XMCD): Difference spectrum of two x-ray absorption spectra (XAS) taken in a magnetic field, one taken with left circularly polarized light, and one with right circularly polarized light. • Coupling between MTb and MNi • is anti-ferromagnetic. • When easy axis of Tb is orthogonal • to Ni, Tb XMCD reduced, signaling • weakening of Tb magnetization.

  5. X-ray Absorption spectra (XAS)

  6. Tuning Exchange Interaction Addition of a oxygen layer between Pc and Ni film results in oxidation of Pc ligand. Exchange field ~ 0.6 T Doping of Ni film with Li leads to reduction of Pc ligand. Exchange field ~ 2.5 T B(T) B(T) (=70o ) (=0o )

  7. (=0o ) (=70o )

  8. Conclusion • SMMs couple to ferromagnetic (FM) metal film. • The superexchange interaction mediating the coupling can be tuned • by oxidizing or reducing the FM substrate. • The SMMs magnetization depends critically on the alignment of the • molecule and substrate easy axis. • The enhanced thermal stability of the TbPc2 magnetic moment and • possibility to orient it parallel or antiparallel to the substrate make • TbPc2 very interesting for application as spin valve device.