Excitations in Heisenberg spin glasses |
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Authors: | U Krey |
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Institution: | (1) Fakultät für Physik der Universität Regensburg, Universitätsstr. 31, D-8400 Regensburg, Fed. Rep. Germany |
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Abstract: | Within the RPA approach forT=0, the excitations of the Heisenberg spin glass system Eu
x
Sr1–x
S are studied by numerical methods, using a continued fraction algorithm. Both the density of statesg(E) and also the spectral functionS(q,E) are calculated for systems with (16)3 sites, withx=0.4, 0.5, and 0.6 (spin glass phase), and also forx0.7 (ferromagnetic phase). Forq-vectors within the (1,1,1) plane,S(q,E) shows magnon peaks even in the spin glass phase, over the whole range ofq. However, these peaks are quite broad, and there is considerable intensity at small energies even for largeq, leading to a finite intercept ofg(E) forE0. Over a large temperature range, the specific heat is approximately linear inT forx0.7. |
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