Electronic and magnetic properties of stoichiometric CeAuBi2

Abstract

We report the electronic and magnetic properties of stoichiometric CeAuBi₂ single crystals. At ambient pressure, CeAuBi₂ orders antiferromagnetically below a Néel temperature (T_N ) of 19 K. Neutron diffraction experiments revealed an antiferromagnetic propagation vector $\hat{\tau }=[0,0,1∕2]$ , which doubles the paramagnetic unit cell along the c axis. At low temperatures several metamagnetic transitions are induced by the application of fields parallel to the c axis, suggesting that the magnetic structure of CeAuBi₂ changes as a function of field. At low temperatures, a linear positive magnetoresistance may indicate the presence of band crossings near the Fermi level. Finally, the application of external pressure favors the antiferromagnetic state, indicating that the 4f electrons become more localized.

FIG. 1.

Crystalline structure of ZrSiS and CeAuBi₂.

FIG. 2.

(a) Specific heat divided by temperature as a function of temperature. Magnetic susceptibility as a function of temperature for fields parallel (b) and perpendicular (c) to the c axis. (d) Magnetization as a function of magnetic field at 2 K for fields parallel and perpendicular to the c axis. The solid red lines are fits using a CEF mean-field model. Note that 1 emu = 10⁻³ Am²

FIG. 3.

(a) Magnetization as a function of applied magnetic fields at different temperatures for fields parallel to the c axis. Solid symbols represent data taken with increasing magnetic field and open symbols with decreasing fields. (b) Critical fields as a function of temperature.

FIG. 4.

(a) AC calorimetry as a function of temperature at several pressures. (b) Electrical resistivity as a function of temperature at several pressures. (c) Temperature-pressure phase diagram for CeAuBi₂.

FIG. 5.

Magnetoresistance (MR) and Hall resistivity (ρ_xy) as a function of applied magnetic field for several pressures at three different temperatures. The solid gray and orange lines are one band and two-band model fits, respectively.

FIG. 6.

(a) (1, 1, 1/2) reflection intensity as a function of temperature. The dashed red line is a mean field fit. The inset shows a schematic representation of the magnetic structure of CeAuBi₂. The error bars are smaller than the data points.