Multi-Q mesoscale magnetism in CeAuSb$_2$

TL;DR

This study uncovers a field-induced transition from a striped to woven spin density wave in CeAuSb$_2$, revealing complex magnetic phases and their evolution under magnetic field in a heavy fermion compound.

Contribution

It reports the first observation of a field-driven transition from striped to woven SDW in CeAuSb$_2$, demonstrating novel magnetic textures in this heavy fermion material.

Findings

Stripe SDW amplitude is 1.8 μ_B/Ce at low T.

Transition from striped to woven SDW occurs at 2.78 T.

Magnetization approaches saturation near 7 T.

Abstract

We report the discovery of a field driven transition from a striped to woven Spin Density Wave (SDW) in the tetragonal heavy fermion compound CeAuSb$_2$. Polarized along $\bf c$, the sinusoidal SDW amplitude is 1.8(2) $\mu_B$/Ce for $T \ll T_N$=6.25(10) K with wavevector ${\bf q}_{1}=( \eta, \eta, \frac{1}{2} )$ ($\eta=0.136(2)$). For ${\bf H}\parallel{\bf c}$, harmonics appearing at $2{\bf q}_{1}$ evidence a striped magnetic texture below $\mu_\circ H_{c1}=2.78(1)$ T. Above $H_{c1}$, these are replaced by woven harmonics at ${\bf q}_{1}+{\bf q}_2=(2\eta, 0, 0)+{\bf c}^*$ until $\mu_\circ H_{c2}=5.42(5)$ T, where satellites vanish and magnetization non-linearly approaches saturation at 1.64(2) $\mu_B$/Ce for $\mu_\circ H\approx 7$ T.