Functional-integral study of spin fluctuations in small Fe clusters

• Published in: The European physical journal. D, Atomic, molecular and optical physics (Print) Vol. 52; no. 1-3; pp. 167 - 170
• Main Authors: Garibay-Alonso, R., Dorantes-Dávila, J., Pastor, G. M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.04.2009; EDP Sciences
• Subjects: Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Atomic and molecular clusters; Atomic and molecular physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic and magnetic properties of clusters; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of nanostructures; Molecular; Nanomagnetism; Optical and Plasma Physics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Information Technology; Quantum Physics; Spectroscopy/Spectrometry; Spintronics; Studies of special atoms, molecules and their ions; clusters; 75.10.Lp Band and itinerant models; 75.75.+a Magnetic properties of nanostructures; 36.40.Cg Electronic and magnetic properties of clusters; Temperature dependence; Monte Carlo methods; Spin fluctuations; Theoretical study; Heisenberg model; Iron; Metal clusters; Atomic clusters; Magnetic properties
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/e2008-00243-7

Finite temperature magnetic properties of small Fe N clusters (N ≤6) are determined in the framework of a spin-fluctuation itinerant-electron theory based on a functional integral formulation of the canonical partition function and derived statistical averages. The free energy associated to each configuration of the exchange fields throughout the cluster are calculated by using Haydock-Heine-Kellys recursion method. The statistical averages of physical interest are obtained by performing parallel-tempering Monte Carlo simulations. Representative results are discussed for the average magnetization per atom as a function of temperature. The interplay between local environment and magnetization curves is analyzed by considering the low-temperature limit of the local spin-fluctuations energies ΔF l (ξ) at different atoms l. The electronic calculations are contrasted with the predictions of simple of phenomenological Heisenberg-like models.