Observation of elastic anomalies driven by coexisting dynamical spin Jahn-Teller effect and dynamical molecular-spin state in the paramagnetic phase of frustrated MgCr 2O 4

Tadataka Watanabe, Shin Ichi Ishikawa, Haruki Suzuki, Yusuke Kousaka, Keisuke Tomiyasu

研究成果: Article

17 引用 (Scopus)

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Ultrasound velocity measurements of the magnesium chromite spinel MgCr 2O 4 reveal elastic anomalies in the paramagnetic phase that are characterized as due to geometrical frustration. The temperature dependence of the tetragonal shear modulus (C 11-C 12)/2 exhibits huge Curie-type softening, which should be the precursor to spin Jahn-Teller distortion in the antiferromagnetic phase. The trigonal shear modulus C 44 exhibits nonmonotonic temperature dependence with a characteristic minimum at ∼50 K, indicating a coupling of the lattice to a dynamical molecular-spin state. These results strongly suggest the coexistence of the dynamical spin Jahn-Teller effect and a dynamical molecular-spin state in the paramagnetic phase, which is compatible with the coexistence of magnetostructural order and a dynamical molecular-spin state in the antiferromagnetic phase.

元の言語English
記事番号144413
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
86
発行部数14
DOI
出版物ステータスPublished - 2012 10 22

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

フィンガープリント Observation of elastic anomalies driven by coexisting dynamical spin Jahn-Teller effect and dynamical molecular-spin state in the paramagnetic phase of frustrated MgCr <sub>2</sub>O <sub>4</sub>' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

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