Figure 1

Field dependence of the Hall resistivity ${\rho }_{xy}$ for (a) ${\mathrm{PdCrO}}_2$ ($T_N=37.5\mathrm{K}$) and for (b) nonmagnetic ${\mathrm{PdCoO}}_2$. (c) Field dependence of the magnetization $M$ for ${\mathrm{PdCrO}}_2$. Insets represent data at temperatures above 40 K. On cooling below $T^{*}\simeq 20\mathrm{K}$, ${\rho }_{xy}$ of ${\mathrm{PdCrO}}_2$ strongly deviates from the linearity and exhibits a hump to positive values at around 10–30 kOe.Reuse & Permissions

Figure 2

(a) Temperature dependence of the magnetic susceptibility of single-crystalline ${\mathrm{PdCrO}}_2$ for fields along the $c$ axis (${\chi }_c=M_c/H$) and in the $ab$ plane (${\chi }_{ab}=M_{ab}/H$) at 70 kOe. (b) Details of the anisotropy below $T_N$. Open (closed) symbols represent data in the field cooling (zero-field cooling) condition. (c) Temperature derivative of ${\chi }_c$ and ${\chi }_{ab}$.Reuse & Permissions

Figure 3

Temperature dependence of $R_S(H,T)$ represented by Eq. (2). $R_S(H,T)$ does not depend on the magnetic field at temperatures above $T^{*}\simeq 20\mathrm{K}$, whereas below $T^{*}$ it is field dependent, indicating the appearance of UAHE.Reuse & Permissions

Figure 4

(a) 3D representation of the overall field and temperature dependence of the Hall conductivity ${\sigma }_{xy}$. (b) Field dependence of ${\sigma }_{xy}$ at temperatures below 40 K. From a point of view based on the scalar spin chirality mechanism, the fictitious field has the opposite sign to the applied magnetic field in the red region in (a).Reuse & Permissions

Figure 5

(a) Positions of Pd and Cr ions in ${\mathrm{PdCrO}}_2$. The arrows represent Cr spins in a 120° spin structure with the antiferromagnetic interlayer coupling. (b) Calculated spin chirality ${\chi }_{ijk}^{\mathrm{Pd}}$ mapping in the Pd-TL net for the modulated Cr spin structure in which the normal vector of the 120° plane precesses. The arrows indicate the exchange field $\mathit{I}$ on Pd ions; the $+$ and $-$ symbols, as well as the red and blue colorings, indicate plus and minus values of ${\chi }_{ijk}^{\mathrm{Pd}}$ of a triangle, respectively. Slight tilt of spins due to the magnetic field leads to overall nonzero chirality. The parameters used in this figure are the precession angle of 5° and the magnetic field strength of 70 kOe. The chirality values are nonlinear in these parameters.Reuse & Permissions