Unique Phase Transition on Spin-2 Triangular Lattice of Ag2MnO2
| Autor: | Yoshihiko Okamoto, Jun-ichi Yamaura, Martin Jansen, Hiroyuki Yoshida, Sascha Ahlert, Zenji Hiroi |
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| Rok vydání: | 2008 |
| Předmět: |
Phase transition
Materials science Curie–Weiss law Strongly Correlated Electrons (cond-mat.str-el) Condensed matter physics Geometrical frustration FOS: Physical sciences General Physics and Astronomy Classical XY model Condensed Matter - Strongly Correlated Electrons Spin crossover Antiferromagnetism Curie temperature Condensed Matter::Strongly Correlated Electrons Hexagonal lattice |
| Zdroj: | Journal of the Physical Society of Japan. 77:074719 |
| ISSN: | 1347-4073 0031-9015 |
| DOI: | 10.1143/jpsj.77.074719 |
| Popis: | Ag2MnO2 is studied as a possible candidate compound for an antiferromagnetic XY spin model on a triangular lattice. In spite of the large Curie-Weiss temperature of -430 K found in magnetic susceptibi-lity, Mn3+ spins with S = 2 do not undergo a conventional long-range order down to 2 K probably owing to the geometrical frustration and two dimensionality in the system. Instead, a unique phase transition is found at 80 K, where specific heat exhibits a clear sign of a second-order phase transition, while magnetic susceptibility changes smoothly without a distinct anomaly. We think that this transition is related to the chirality degree of freedom associated with a short-range order, which has been expected for the classical XY spin model on a triangular lattice. On further cooling, spin-glass-like behavior is observed below 22 K, possibly corresponding to a quasi-long-range order. Comment: to appear in J. Phys. Soc. Jpn, Vol. 77, No. 7 |
| Databáze: | OpenAIRE |
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