Effect of uniaxial stress on the magnetic phases of CeAuSb${}_2$

Abstract

We present results of measurements of resistivity of \CAS{} under the combination of $c$-axis magnetic field and in-plane uniaxial stress. In unstressed \CAS{} there are two magnetic phases. The low-field A phase is a single-component spin-density wave (SDW), with $\mathbf{q}=(\eta ,\pm \eta ,1/2)$, and the high-field B phase consists of microscopically coexisting $(\eta ,\eta ,1/2)$ and $(\eta ,-\eta ,1/2)$ spin-density waves. Pressure along a $⟨100⟩$ lattice direction is a transverse field to both of these phases, and so initially has little effect, however eventually induces new low- and high-field phases in which the principal axes of the SDW components appear to have rotated to the $⟨100⟩$ directions. Under this strong $⟨100⟩$ compression, the field evolution of the resistivity is much smoother than at zero strain: In zero strain, there is a strong first-order transition, while under strong $⟨100⟩$ it becomes much broader. We hypothesize that this is a consequence of the uniaxial stress lifting the degeneracy between the (100) and (010) directions.

8 pages, 7 figures