[Mn12O12(O2CR)16(H2O)4]
clusters: towards the obtaining of single-molecule magnets
Daniel Ruiza,c, Concepció
Rovira,a Jaume Vecianaa*, George Christoub*
and David N.Hendricksonc*
aInstitut de Ciencia de Materials, Campus U.A.B, 08193,
Bellaterra, Spain
bDepartment of Chemistry-0358, University of California
at San Diego, La Jolla, California 92093-0358
cDepartment of Chemistry, Indiana University, Bloomington,
Indiana 47405-4001, U.S.A
The miniaturization of magnetic technology as well as the rapid growth
of high-speed computers have attracted much more interest in the field
of nanoscale magnetic materials. One main problem is that since nanoscale
magnetic materials are usually made by fragmenting bulk ferromagnets, a
distribution of particle sizes, anisotropy and shape is present. This situation
leads to a distribution of the barrier heights for the interconversion
of the spins "up" to the spins "down" within the domain that is not desirable
for application in devices as it often compromises performance. To avoid
such distribution of barrier heights more recently "engineering-up" methodologies
using synthetic approaches have become an attractive prospect. In this
order monodispersed and large metal cluster complexes with interesting
magnetic properties characteristic of nanoscale magnetic particles, such
as magnetization hysteresis loops and out-of-phase ac magnetic susceptibility
signals, have been synthesized. In addition, steps at a constant interval
of field in the magnetization hysteresis loops originated by the Magnetization
Quantum Tunneling have also been observed.
In this communication, we will focus our attention towards the family
of Mn12 complexes and some other molecular solids that can be
derived from them and that have been extensively studied in our groups.
