Difference in elastic properties of CrB2 determined by microscopic and macroscopic measurements

Katsushi Tanaka, Satoshi Tsutsui, Norihiko L. Okamoto, Haruyuki Inui, Alfred Q.R. Baron

研究成果: Conference contribution

抄録

CrB2 possess the hexagonal AlB2 structure which belongs to the spacegroup of P6/mmm. The compound exhibits para- to antiferro-magnetic transition at about 88 K. By using a macroscopic measurement technique, that is, a conventional resonant ultrasound spectroscopy (RUS) with a millimeter size mono-crystal, significant elastic anomalies have been observed just above the magnetic transition temperature. On the other hand, elastic constants determined by a microscopic measurement technique, that is, an inelastic X-ray scattering method (BL35XU of SPring-8, Japan) do not show any elastic anomalies at around the transition temperature. In order to explain the discrepancy, we have introduced a kind of so called ΔE effect resulting from a multidomain structure. If crystal lattice is slightly deformed by a spontaneous magnetostriction in the antiferromagnetic state, the symmetry of crystal lattice is lowered from hexagonal to monoclinic when the symmetry of magnetic structure is taken into account. By the lowering of the symmetry, the crystal consists of six magnetic domains in the antiferro magnetic state. If magnetic domain boundaries move in response to externally applied stresses, the mechanical deformation is absorbed by nonelastic deformations induced by the movement of magnetic domain boundaries. This multidomain model well explains the experimental results obtained by both microscopic (X-ray) and macroscopic (ultrasound) measurements. The microscopic measurement technique is useful to obtain the true elastic properties of crystal lattice without effects coming from a multidomain structure.

本文言語English
ホスト出版物のタイトルAdvanced Materials Exploration with Neutrons and Synchrotron X-Rays
出版社Materials Research Society
ページ77-82
ページ数6
ISBN(印刷版)9781632661180
DOI
出版ステータスPublished - 2013
外部発表はい
イベント2012 MRS Fall Meeting - Boston, MA, United States
継続期間: 2012 11 252012 11 30

出版物シリーズ

名前Materials Research Society Symposium Proceedings
1528
ISSN(印刷版)0272-9172

Other

Other2012 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period12/11/2512/11/30

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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