Quantum coherence in molecular nanomagnets

¹ Departament de Física Fonamental, Universitat de Barcelona Diagonal 647, 08028 Barcelona, Spain
² Laboratoire de Physique des Solides, Bâtiment 510, Université Paris-Sud 91405 Orsay, France
³ Physics Department, CUNY Lehman College, Bronx, NY 10468-1589, USA
⁴ ICMAB (CSIC), Campus Universitat Autonoma de Barcelona 08193 Cerdanyola, Spain

Received: 17 May 1999
Accepted: 14 July 1999

Abstract

We report observation of coherent quantum oscillations in spin-10 Fe₈ molecular clusters. The powder of magnetically oriented Fe₈ crystallites was placed inside a resonator, in a dc magnetic field perpendicular to the magnetization axis. The field dependence of the ac-susceptibility was measured up to 5 T, at 680 MHz, down to 25 mK. Two peaks in the imaginary part of the susceptibility have been detected, whose positions coincide, without any fitting parameters, with the predicted two peaks corresponding to the quantum splitting of the ground state in the magnetic field parallel and perpendicular to the hard magnetization axis.