Effect of applied orthorhombic lattice distortion on the antiferromagnetic phase of CeAuSb2

Abstract

We study the response of the antiferromagnetism of CeAuSb2 to orthorhombic lattice distortion applied through in-plane uniaxial pressure. The response to pressure applied along a 110 lattice direction shows a first-order transition at zero pressure, which shows that the magnetic order lifts the (110)/(110) symmetry of the unstressed lattice. Sufficient 100 pressure appears to rotate the principal axes of the order from 110 to 100 . At low 100 pressure, the transition at TN is weakly first-order, however it becomes continuous above a threshold 100 pressure. We discuss the possibility that this behavior is driven by order parameter fluctuations, with the restoration of a continuous transition a result of reducing the point-group symmetry of the lattice.

Effect of uniaxial stress on the magnetic phases of CeAuSb2

“…It incorporates a displacement sensor placed in parallel with the sample. As in previous reports [8,13], we estimate that ∼80% of the applied displacement is transferred to the central, exposed portion of the sample, with the rest going into deformation of the ends of the sample and the epoxy. In other words, the strains reported here are the applied displacement divided by the exposed length of the sample, multiplied by 0.8, and we estimate a ∼20% sample-tosample error on this strain determination.…”

“…[3] the nearvertical transition lines at H1 and H2 were found to be first order, and in Ref. [13] the transition at H = 0, T = TN was also found to be, probably, weakly first order. (b) and (c) Schematic H = 0 strain-temperature phase diagrams, such as they could be resolved in measurements, for pressure applied along a (b) 110 lattice direction, and (c) 100 direction.…”

Nematic State in CeAuSb2

“…In order to understand the origin of T Ã and the other phases denoted by (M', M", and M*) under pressure, the underlying magnetic structures will have to be determined by neutron or nuclear magnetic resonance measurements under applied pressure and field. Interestingly, experiments on CeAuSb 2 under uniaxial strain along the ½100 direction also suggest additional magnetic phases [30,31]. In particular, the H − T phase diagram under applied compression along the ½100 direction resembles our phase diagram in Fig.…”

“…As a result, one expects that the lattice will also break tetragonal C 4 symmetry in the presence of magnetoelastic coupling. In fact, in-plane uniaxial pressure experiments show that the magnetic transitions of CeAuSb 2 are sensitive to strain [30,31]. The situation thus seems analogous to iron-based high-T c superconductors such as NaFeAs ("111") and LaFeAsO ("1111"), which share the same P4=nmm space group as CeAuSb 2 [32,33].…”

Apparatus design for measuring of the strain dependence of the Seebeck coefficient of single crystals

“…In the past few years, in-situ tunable strain has proven to be a powerful tool to probe and control exotic phases in both topological 5,6 and strongly correlated materials [7][8][9][10] . Most of the in-situ strain work to date relies on the measurement of electrical resistivity as a probe of the electronic structures.…”