Pregled bibliografske jedinice broj: 176089
Macroscopic quantum tunneling in Mn12-acetat
Macroscopic quantum tunneling in Mn12-acetat // 54. Jahrestagung der Oesterreichischen Physikalischen Gesellschaft / Lippitsch, M (ur.).
Linz: Oesterreichische Physikalische Gesellschaft, 2004. str. 100-100 (poster, nije recenziran, sažetak, znanstveni)
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Naslov
Macroscopic quantum tunneling in Mn12-acetat
Autori
Beiter, Johannes ; Reissner, Michael ; Hilscher, G ; Steiner, Walter ; Pajić, Damir ; Zadro, Krešo ; Bartel, M ; Linert, W
Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni
Izvornik
54. Jahrestagung der Oesterreichischen Physikalischen Gesellschaft
/ Lippitsch, M - Linz : Oesterreichische Physikalische Gesellschaft, 2004, 100-100
Skup
54. Jahrestagung der Oesterreichischen Physikalischen Gesellschaft
Mjesto i datum
Linz, Austrija, 28.09.2004. - 30.09.2004
Vrsta sudjelovanja
Poster
Vrsta recenzije
Nije recenziran
Ključne riječi
single molecule magnet; Mn12-acetate; macroscopic quantum tunneling
Sažetak
Molecules provide the exciting opportunity to study magnetism on the passage from atomic to macroscopic level. One of the most interesting effects in such mesoscopic systems is the appearance of quantum tunnelling of magnetization (MQT) at low temperatures. In the last decade molecular chemistry has had a large impact in this field by providing new single molecule magnets. They consist of small clusters exhibiting superparamagnetic behaviour, similar to that of conventional nanomagnetic particles. The advantage of these new material is that they form macroscopic samples consisting of regularly arranged small identical high-spin clusters which are widely separated by organic molecules. The lack of distributions in size and shape of the magnetic clusters and the very weak intercluster interaction lead in principle to only one barrier for the spin reversal. We present detailed magnetic investigations on a Mn12-ac single crystal. In this compound the tetragonal ordered cluster consist of a central tetrahedron of four Mn4+ (S=3/2) atoms surrounded by eight Mn3+ (S=2) atoms with antiparallel oriented spins, leading to an overall spin moment of S=10. In the hysteresis loops nine different jumps at regularly spaced fields are identified in the investigated temperature range (1.5K<T<3K). At these fields the relaxation of moment due to thermal activation is superimposed by strong quantum tunnelling. In lowering the temperature the time dependence changes from thermally activated to thermally assisted tunneling.
Izvorni jezik
Engleski
Znanstvena područja
Fizika
