Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 36: Micro- and Nanostructured Magnetic Materials III
MA 36.4: Vortrag
Mittwoch, 16. März 2011, 15:30–15:45, HSZ 103
Influence of crystallite size and temperature on the antiferromagnetic helices of terbium and holmium metal — •Jens-Peter Bick1,2, Andreas Michels1,2, Adrian Ferdinand1, Rainer Birringer1, Jörg Baller2, Roland Sanctuary2, Stefan Philippi3, Dieter Lott4, Sandor Balog5, Eli Rotenberg6, Günter Kaindl7, and Kristian M. Döbrich7,8 — 1Universität des Saarlandes, D-66041 Saarbrücken — 2University of Luxembourg, L-1511 Luxembourg — 3Leibniz Institute for Solid State and Materials Research, D-01069 Dresden — 4GKSS Research Center, D-21502 Geesthacht — 5Paul Scherrer Institute, CH-5232 Villigen — 6Lawrence Berkeley National Laboratory, California 94720, USA — 7Freie Universität Berlin, D-14195 Berlin-Dahlem — 8Max-Born-Institut, D-12489 Berlin
We report on the results of grain-size and temperature-dependent magnetization, specific-heat, neutron-scattering, and angle-resolved photoelectron spectroscopy (ARPES) experiments on the heavy rare-earth metals terbium and holmium, with particular emphasis on the temperature regions where the helical antiferromagnetic phases exist. In contrast to Ho, we find that the helical structure in Tb is relative strongly affected by microstructural disorder, specifically, it can no longer be detected for the smallest studied grain size of D=18 nm . Moreover, in coarse-grained Tb a helical structure persists even in the ferromagnetic regime, down to about T=215 K , in agreement with the ARPES data, which reveal a nesting feature of the Fermi surface at the L point of the Brillouin zone at T=210 K .