Modulated Magnetism and Anomalous Electronic Transport in Ce3Cu4As4O2
Jiakui K. Wang, Shan Wu, Yiming Qiu, Jose Rodriguez Rivera, Qingzhen Huang, Collin L. Broholm, E. Morosan
The complex magnetism and transport properties of tetragonal Ce3Cu4As4O2 were examined through neutron scattering and physical properties measurements on polycrystalline samples. The lamellar structure consists of alternating layers of CeCu4As4 with a single square Ce lattice and Ce2O2 bi-layers. Peaks in the specific heat at the Neel temperature TN = 25 K, T2 = 16 K and T3 = 1.9 K indicate three magnetic Phase transitions or distinct cross-over phenomena. For TN neutron diffraction indicates the development of ferromagnetic ab sheets for both Ce sites, with alternating polarization along c, and a wave vector k1 = c*. For T2, quasi-two-dimensional low-energy spin fluctuations with ld2 = 1⁄2a* and polarized perpendicular to k2are suppressed. The data are consistent with quasi-two-dimensional antiferromagnetic order in the CeCu4As4 polarized along the k2 wave vector. Td3^ marks a spin-flop transition where the k1 staggered magnetization switches to in-plan polarization. There are significant transport anomalies associated with the transitions, in particular a substantial reduction in resistivity for TN. At T = 100 mK the magnetic correlation length exceeds 75 A and the k1 modulated staggered moment is 0.85 υB, which matches the 0.8 υB saturation magnetization achieved for υοH = 7 T at T = 2 K. We trace the unusual sequence of magnetic transitions to competing interactions and anisotropies in the alternating quasi-two-dimensional magnetic layers.
, Wu, S.
, Qiu, Y.
, Rodriguez Rivera, J.
, Huang, Q.
, Broholm, C.
and Morosan, E.
Modulated Magnetism and Anomalous Electronic Transport in Ce<sub>3</sub>Cu<sub>4</sub>As<sub>4</sub>O<sub>2</sub>, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921570
(Accessed December 9, 2023)