Dipolar ordering in ?
Departament de Física Fonamental, Universitat de
Barcelona Diagonal 647, 08028 Barcelona, Spain
2 Department of Physics and Astronomy, Lehman College, City University of New York Bedford Park Boulevard West, Bronx, New York 10468-1589, USA
3 School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University - Tel Aviv 69978, Israel
Accepted: 16 May 2001
We show that the low-temperature physics of molecular nanomagnets, contrary to the prevailing one-molecule picture, must be determined by the long-range magnetic ordering due to many-body dipolar interactions. The calculations here performed, using Ewald's summation, suggest a ferromagnetic ground state with a Curie temperature of about 130 mK. The energy of this state is quite close to those of an antiferromagnetic state and to a glass of frozen spin chains. The latter may be realized at finite temperature due to its high entropy.
PACS: 75.50.Xx – Molecular magnets / 75.45.+j – Macroscopic quantum phenomena in magnetic systems
© EDP Sciences, 2001