Induced ferromagnetic interactions in Langmuir-Blodgett films of an organic radical

The elaboration of a purely organic ferromagnet requires a precise supramol ecular organization, but up to now, it has proven impossible to control or even predict the way a given molecule will crystallize. We present here res ults showing that the Langmuir-Blodgett technique allows for such a control . Starting from a material with antiferromagnetic intermolecular interactio ns, we have been able to build monolayer Langmuir-Blodgett films with ferro magnetic interactions, as evidenced by electron spin resonance measurements .