title: Thermodynamics of the Mn(12)-ac molecule in a skew magnetic field at [Formula: see text] K.
abstract: We derive the high-temperature expansion of the Helmholtz free energy of the quantum and classical models for the Mn(12)-ac molecule in the presence of a skew magnetic field, including the transverse term in the Hamiltonians, for [Formula: see text] K. In this region of temperature, we show that the transverse term can give a measurable contribution to the x component of the magnetization. We obtain the specific heat per site of a powder sample of Mn(12)-ac under a constant magnetic field. For strong skew magnetic fields (h/D>1), the specific heat differs up to 20% from its value of a crystal sample under purely longitudinal magnetic fields. Finally, we obtain that in the limit [Formula: see text], the values of the classical and quantum specific heat differ; in particular, for [Formula: see text] this difference is 0.96%.
authors.affiliation: Departamento de Ciências Exatas, Universidade Federal de Lavras, Caixa Postal 3037, CEP 37200-000, Lavras-MG, Brazil.
authors.forename: Onofre
authors.initials: O
authors.lastname: Rojas
authors.forename: M T
authors.initials: MT
authors.lastname: Thomaz
authors.forename: E V
authors.initials: EV
authors.lastname: Corrêa Silva
authors.forename: S M
authors.initials: SM
authors.lastname: de Souza