2018年2月28日
Critical behavior of magnetization in URhAl: Quasi-two-dimensional Ising system with long-range interactions
Physical Review B
- ,
- ,
- ,
- 巻
- 97
- 号
- 6
- 開始ページ
- 064423-1
- 終了ページ
- 064423-10
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1103/PhysRevB.97.064423
- 出版者・発行元
- American Physical Society
The critical behavior of dc magnetization in the uranium ferromagnet URhAl with the hexagonal ZrNiAl-type crystal structure has been studied around the ferromagnetic transition temperature TC. The critical exponent β for the temperature dependence of the spontaneous magnetization below TC,γ for the magnetic susceptibility, and δ for the magnetic isotherm at TC, have been obtained with a modified Arrott plot, a Kouvel-Fisher plot, the critical isotherm analysis, and the scaling analysis. We have determined the critical exponents as β=0.287±0.005, γ=1.47±0.02, and δ=6.08±0.04 by the scaling analysis and the critical isotherm analysis. These critical exponents satisfy the Widom scaling law δ=1+γ/β. URhAl has strong uniaxial magnetic anisotropy, similar to its isostructural UCoAl that has been regarded as a three-dimensional (3D) Ising system in previous studies. However, the universality class of the critical phenomenon in URhAl does not belong to the 3D Ising model (β=0.325, γ=1.241, and δ=4.82) with short-range exchange interactions between magnetic moments. The determined exponents can be explained with the results of the renormalization group approach for a two-dimensional (2D) Ising system coupled with long-range interactions decaying as J(r)∼r-(d+σ) with σ=1.44. We suggest that the strong hybridization between the uranium 5f and rhodium 4d electrons in the U-RhI layer in the hexagonal crystal structure is a source of the low-dimensional magnetic property. The present result is contrary to current understandings of the physical properties in a series of isostructural UTX uranium ferromagnets (T: transition metals, X: p-block elements) based on the 3D Ising model.
- リンク情報
- ID情報
-
- DOI : 10.1103/PhysRevB.97.064423
- ISSN : 2469-9969
- ISSN : 2469-9950
- SCOPUS ID : 85043778589
- Web of Science ID : WOS:000426321000003