1. Coupling Single Molecule Magnets to Ferromagnetic Substrates

2.  Double Decker Structure  Electronic config. of Tb: [Xe]4f 9 6s 2 Phthalocyanine  C 32 H 18 N 8 TbPc 2 (Terbium-Phthalocyanino) SMM

3. Easy axis of Ni:  Out of Plane (OP) of Ni film and collinear with TbPc 2 axis.  OP axis is created by adding 13 monolayers of Ni on Cu(100) surface. Experimental Setup Easy axis of Ni:  In Plane (IP) of Ni film and perpendicular to TbPc 2 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 (  =0 o ) and grazing (  =70 o ) 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 M Tb and M Ni 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)

7. 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) (  =0 o ) (  =70 o ) B(T) Tuning Exchange Interaction

8. (  =0 o )(  =70 o )

10. 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 TbPc 2 magnetic moment and possibility to orient it parallel or antiparallel to the substrate make TbPc 2 very interesting for application as spin valve device.