Incommensurate Magnetism in FeAs Strips: Neutron Scattering from CaFe${}_4$As${}_3$

Abstract

Magnetism in the orthorhombic metal CaFe${}_4$As${}_3$ was examined through neutron diffraction for powder and single crystalline samples. Incommensurate (${\mathbf{q}}_{\mathrm{m}}\approx (0.37-0.39)\times {\mathbf{b}}^{\ast }$) and predominantly longitudinally ($\parallel b$) modulated order develops through a 2nd order phase transition at $T_{\mathrm{N}}=89.63(6)$ K with a 3D Heisenberg-like critical exponent $\beta =0.365(6)$. A 1st order transition at $T_2=25.6(9)$ K is associated with the development of a transverse component, locking ${\mathbf{q}}_{\mathrm{m}}$ to $0.375(2){\mathbf{b}}^{\ast }$, and increasing the moments from 2.1(1) to 2.2(3) ${\mu }_{\mathrm{B}}$ for Fe${}^{2+}$ and from 1.3(3) to 2.4(4) ${\mu }_{\mathrm{B}}$ for Fe${}^{+}$. The {\it ab-initio} Fermi surface is consistent with a nesting instability in cross-linked FeAs strips.

5 pages, 5 figures, accepted for publication in Phys. Rev. Lett

References in corpus (4)

• To What Extent Iron-Pnictide New Superconductors Have Been Clarified: A Progress Report
• Incommensurate magnetic order in the alpha-Fe(Te,Se) superconductor systems
• Chalcogen-height dependent magnetic interactions and magnetic order switching in FeSe${}_x$Te${}_{1-x}$
• Dispersion of the superconducting spin resonance in underdoped and antiferromagnetic Ba(Fe1-xCox)2As2

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