Nematic-to-smectic transition of magnetic texture in conical state

コニカル状態での磁区構造が示すネマチック-スメクチック相転移

武田 全康  ; 遠藤 康夫; 加倉井 和久; 小野瀬 佳文*; 鈴木 淳市; 十倉 好紀*

Takeda, Masayasu; Endo, Yasuo; Kakurai, Kazuhisa; Onose, Yoshinori*; Suzuki, Junichi; Tokura, Yoshinori*

FeCoSiの長距離磁気秩序状態が示す複雑な磁気相転移の様子を低温,外部磁場下で中性子小角散乱によって調べた。リング状,三日月状,ぼやけた回折線など、温度と外部磁場によってさまざまな散乱パターンが現れた。この結果は、磁化を液晶の配向ベクトルとみなすことで、液晶で見られる相転移との類似性を明らかにした。

The complex phase transition of the magnetic long-range order in FeCoSi has been investigated by small-angle neutron scattering (SANS) measurement at low temperatures under an external magnetic field. A variety of scattering patterns, such as ring, crescent-shaped, and diffusive spots, were observed by changing temperature and applying a magnetic field. The results could be interpreted by an analogy of the phase transition of the liquid crystal when the net magnetization is regarded as the director of the liquid crystal.