Magnetic and electronic structure of the layered rare-earth pnictideEuCd2Sb2

Abstract

Resonant elastic X-ray scattering (REXS) at the Eu M5 edge reveals an antiferromagnetic structure in layered EuCd2Sb2 at temperatures below TN = 7.4 K with a magnetic propagation vector of (0, 0, 1/2) and spins in the basal plane. Magneto-transport and REXS measurements with an in-plane magnetic field show that features in the magnetoresistance are correlated with changes in the magnetic structure induced by the field. Ab initio electronic structure calculations predict that the observed spin structure gives rise to a gapped Dirac point close to the Fermi level with a gap of ∆E ∼ 0.01 eV. The results of this study indicate that the Eu spins are coupled to conduction electron states near the Dirac point.

Resonant x-ray scattering study of diffuse magnetic scattering from the topological semimetals EuCd2As2 and EuCd2Sb2Soh1, Schierle2, Yan3 et al. 2020Phys. Rev. BSelf Cite25160View full textAdd to dashboardCite

“…Comprehensive magnetization, magnetotransport, and laboratory x-ray diffraction characterizations of our samples have been reported in Refs. [28,36,37] and are fully consistent with other reports on EuCd 2 Pn 2 [27,35,[38][39][40][41][42].…”

“…2(e). These Néel temperatures are consistent with earlier REXS studies [36,37]. The shaded area in Fig.…”

“…Single-crystalline EuCd 2 As 2 and EuCd 2 Sb 2 were grown by self-flux and chemical vapor transport methods, respectively, as described in Refs. [35,36]. Comprehensive magnetization, magnetotransport, and laboratory x-ray diffraction characterizations of our samples have been reported in Refs.…”

Colossal Magnetoresistance without Mixed Valence in a Layered Phosphide Crystal

“…We show one magnetic unit cell in Figure 2a where the order is FM within the Eu layers but with alternating direction (AFM) between the layers. This A-type AFM order has been previously reported in crystals of EuCd2As2 and EuCd2Sb2, [23][24][25][26][27] and is consistent with the magnetic susceptibility data in Figure 2b that shows a FM order when H∥ab, but an AFM order when H∥c. The finite residual χc(T) near zero temperature indicates a small out-of-plane spin canting superposed on the A-type AFM order.…”

“…Simultaneously the exchange correlations are expected to grow from X = Sb to As and P, leading to an increase in T N from 7 to 9 and 11 K, respectively. [ 23–25 ] The buildup of correlations is evident in Figure 4d where both the violation of the Ioffe‐Regel limit (ρ > 1 mΩ cm) in the bad metal regime (inset) and the resistivity peak near T N are dramatically enhanced by replacing Sb with As and P.…”