Finite-size effect on magnetic ordering temperatures in long-period antiferromagnets: holmium thin films.
The thickness dependence of the helical antiferromagnetic ordering temperature T(N) was studied for thin Ho metal films by resonant magnetic soft x-ray and neutron diffraction. In contrast with the Curie temperature of ferromagnets, T(N) was found to decrease with film thickness d according to [T(N)(infinity)-T(N)(d)]/T(N)(d) proportional variant (d-d(0))(-lambda(')), where lambda(') is a phenomenological exponent and d(0) is of the order of the bulk magnetic period L(b). These observations are reproduced by mean-field calculations that suggest a linear relationship between d(0) and L(b) in long-period antiferromagnets.
Weschke
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Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany. eugen.weschke@physik.fu-berline.de
Ott
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Schierle
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Schüssler-Langeheine
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Vyalikh
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Kaindl
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Leiner
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Ay
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Schmitte
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Zabel
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Jensen
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