Formation of ferromagnetic molecular thin films from blends by annealing

Abstract

We report on a new approach for the fabrication of ferromagnetic molecular thin films. Co-evaporated films of manganese phthalocyanine (MnPc) and tetracyanoquinodimethane (TCNQ) have been produced by organic molecular beam deposition (OMBD) on rigid (glass, silicon) and flexible (Kapton) substrates kept at room temperature. The MnPc:TCNQ films are found to be entirely amorphous due to the size mismatch of the molecules. However, by annealing while covering the samples highly crystalline MnPc films in the β-polymorph can be obtained at 60 °C lower than when starting with pure MnPc films. The resulting films exhibit substantial coercivity (13 mT) at 2 K and a Curie temperature of 11.5 K.

Towards molecular spintronics

“…The range of considered molecules spans from heterotrinuclear bis(oxamato)-type and bis(oxamidato)-type complexes [ 1 – 3 ], to exchange-coupled dinickel complexes [ 4 ], metallo-phthalocyanines [ 5 – 7 ], metallo-porphyrins [ 8 – 9 ] and charge-transfer complexes [ 10 – 11 ], to metal-free molecules like pentacene-derivatives [ 12 ], fullerenes [ 13 ], trimesic acid [ 14 ], or organic ferromagnets [ 15 ]. Besides the internal cooperation, the Research Unit greatly profited from excellent talks and thorough discussions with external guests joining our scientific workshops and we are happy to host six articles from our invited guests with topics beyond the molecular systems investigated in our Research Unit, for example: theoretical predictions on metal/C 60 interfaces [ 16 ], magneto-resistive donor/acceptor transistors [ 17 ], spin-crossover complexes [ 18 ], ferromagnetic thin films obtained from organic blends [ 19 ], and theoretical calculations on 2D porphyrin-based networks for spintronics [ 20 ]. We are also happy to host a review paper entitled “Spin-chemistry concepts for spintronics scientists” [ 21 ], which discusses the vast terminology differences and addresses the benefits that might arise from a stronger interaction between spin-chemistry and spintronics, thereby opening the horizon for future progress in both fields.…”