Multi-Q mesoscale magnetism in CeAuSb${}_2$

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 $\mathbf{c}$, the sinusoidal SDW amplitude is 1.8(2) ${\mu }_B$/Ce for $T\ll T_N$=6.25(10) K with wavevector ${\mathbf{q}}_1=(\eta ,\eta ,\frac{1}{2})$ ($\eta =0.136(2)$). For $\mathbf{H}\parallel \mathbf{c}$, harmonics appearing at $2{\mathbf{q}}_1$ evidence a striped magnetic texture below ${\mu }_{\circ }{H}_{c1}=2.78(1)$ T. Above $H_{c1}$, these are replaced by woven harmonics at ${\mathbf{q}}_1+{\mathbf{q}}_2=(2\eta ,0,0)+{\mathbf{c}}^{\ast }$ 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.

5 pages, 4 figures