Magnetic structure and resistivity minimum in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>GdCuAs</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math>

The electrical resistivity of ${\mathrm{GdCuAs}}_{2}$ single crystals exhibits an anomalous Kondo-like resistivity minimum above the antiferromagnetic ordering temperature ${T}_{{\mathrm{N}}_{1}}\ensuremath{\approx}$ 10.6 K, which is unusual for a highly localized $4f$-moment (${\mathrm{Gd}}^{3+}$) system. Using x-ray resonant magnetic scattering, we determined the magnetic structure of ${\mathrm{GdCuAs}}_{2}$, where Gd moments are antiferromagnetically aligned along the crystallographic a axis and in the $(++\ensuremath{-}\ensuremath{-})$ arrangement in the c direction and ferromagnetically arranged in the b direction. The antiferromagnetic order appears first at q = ($\ensuremath{\delta}$, 0, 0.5) below 10 K, with an incommensurate modulation along the a axis and locks into a commensurate position at q = (1/3, 0, 0.5) below ${T}_{{\mathrm{N}}_{2}}\ensuremath{\approx}$ 6 K. Our high-resolution x-ray diffraction measurements show a two-peak structure at Q = (2, 0, 6) above the resistivity minimum, suggesting a lower-symmetry crystal structure than the reported tetragonal structure, and the Q = (2, 0, 6) peak becomes a sharp one-peak structure below the resistivity minimum, implying a magnetoelastic coupling above ${T}_{\mathrm{N}}$. Our findings suggest a complex interplay between the crystal structure and antiferromagnetic structure through a magnetoelastic coupling, associated with the anomalous resistivity minimum above ${T}_{{\mathrm{N}}_{1}}$.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.