Realization of the Axial Next-Nearest-Neighbor Ising model in U${}_3$Al${}_2$Ge${}_3$

Abstract

Here we report small-angle neutron scattering (SANS) measurements and theoretical modeling of U${}_3$Al${}_2$Ge${}_3$. Analysis of the SANS data reveals a phase transition to sinusoidally modulated magnetic order, at $T_{\mathrm{N}}=63$~K to be second order, and a first order phase transition to ferromagnetic order at $T_{\mathrm{c}}=48$~K. Within the sinusoidally modulated magnetic phase ($T_{\mathrm{c}}<T<T_{\mathrm{N}}$), we uncover a dramatic change, by a factor of three, in the ordering wave-vector as a function of temperature. These observations all indicate that U${}_3$Al${}_2$Ge${}_3$ is a close realization of the three-dimensional Axial Next-Nearest-Neighbor Ising model, a prototypical framework for describing commensurate to incommensurate phase transitions in frustrated magnets.

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Cited by in corpus (1)

• Noncoplanar multiple-$Q$ spin textures by itinerant frustration: Effects of single-ion anisotropy and bond-dependent anisotropy