Magnetic structures of rare earth intermetallic compounds RCuAs$_2$ (R = Pr, Nd, Tb, Dy, Ho, and Yb)

Y. Zhao; J. W. Lynn; Gohil S. Thakur; Zeba Haque; L. C. Gupta; A K Ganguli

doi:10.1016/j.jpcs.2017.07.004

paper

Magnetic structures of rare earth intermetallic compounds RCuAs $_{2}$ (R = Pr, Nd, Tb, Dy, Ho, and Yb)

arXiv:1603.03704 · doi:10.1016/j.jpcs.2017.07.004

Abstract

Neutron scattering studies have been carried out on polycrystalline samples of a series of rare earth intermetallic compounds RCuAs $_{2}$ (R = Pr, Nd, Dy, Tb, Ho and Yb) as a function of temperature to determine the magnetic structures and the order parameters. These compounds crystallize in the ZrCuSi $_{2}$ type structure, which is similar to that of the RFeAsO (space group P4/nmm) class of iron-based superconductors. PrCuAs $_{2}$ develops commensurate magnetic order with K = (0, 0, 0.5) below T $_{N}$ = 6.4 (2) K, with the ordered moments pointing along the c-axis. The irreducible representation analysis shows either a $Γ$ $_{2}^{1}$ or $Γ$ $_{3}^{1}$ representation. NdCuAs $_{2}$ and DyCuAs $_{2}$ order below T $_{N}$ = 3.54(5) K and T $_{N}$ = 10.1(2) K, respectively, with the same ordering wave vector but the moments lying in the a-b plane (with a $Γ$ $_{9}^{2}$ or $Γ$ $_{10}^{2}$ representation). TbCuAs $_{2}$ and HoCuAs $_{2}$ exhibit incommensurate magnetic structures below T $_{N}$ = 9.44(7) and 4.41(2) K, respectively. For TbCuAs $_{2}$ , two separate magnetic ordering wave vectors are established as K $_{1 (T b)}$ = (0.240,0.155,0.48) and K $_{2 (T b)}$ = (0.205, 0.115, 0.28), whereas HoCuAs $_{2}$ forms a single K $_{(H o)}$ = (0.121, 0.041, 0.376) magnetic structure with 3 $^{r d}$ order harmonic magnetic peaks. YbCuAs $_{2}$ does not exhibit any magnetic Bragg peaks at 1.5 K, while susceptibility measurements indicate an antiferromagnetic-like transition at 4 K, suggesting that either the ordering is not long range in nature or the ordered moment is below the sensitivity limit of $\approx$ 0.2 $μ_{B}$ .

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High-temperature superconductivity in iron-based materials

Magnetic structures of rare earth intermetallic compounds RCuAs2​ (R = Pr, Nd, Tb, Dy, Ho, and Yb)

Abstract

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Magnetic structures of rare earth intermetallic compounds RCuAs $_{2}$ (R = Pr, Nd, Tb, Dy, Ho, and Yb)