Quantum Interference Oscillations of the Superparamagnetic Blocking in an Fe8 Molecular Nanomagnet

Enrique Burzuri (1) , Fernando Luìs (1) , Oscar Montero (1) , Bernard Barbara (2) , Rafik Ballou (3) , Satoru Maegawa (4)

1 ICMA-CSIC - Instituto de Ciencia de Materiales de Aragón [Saragoza, España]
2 NEEL - QuantECA - Circuits électroniques quantiques Alpes
3 NEEL - MagSup - Magnétisme et Supraconductivité
4 Graduate School of Human and Environmental Studies - Kyoto University

We show that the dynamic magnetic susceptibility and the superparamagnetic blocking temperature of an Fe8 single molecule magnet oscillate as a function of the magnetic field Hx applied along its hard magnetic axis. These oscillations are associated with quantum interferences, tuned by Hx, between different spin tunneling paths linking two excited magnetic states. The oscillation period is determined by the quantum mixing between the ground S ¼ 10 and excited multiplets. These experiments enable us to quantify such mixing. We find that the weight of excited multiplets in the magnetic ground state of Fe8 amounts to approximately 11.6%.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Enrique Burzuri, Fernando Luìs, Oscar Montero, Bernard Barbara, Rafik Ballou, et al.. Quantum Interference Oscillations of the Superparamagnetic Blocking in an Fe8 Molecular Nanomagnet. Physical Review Letters, 2013, 111, pp.057201. ⟨10.1103/PhysRevLett.111.057201⟩. ⟨hal-00963853⟩