Modulated Magnetism and Anomalous Electronic Transport in Ce3Cu4As4O2

Published

August 29, 2016

Author(s)

Jiakui K. Wang, Shan Wu, Yiming Qiu, Jose Rodriguez Rivera, Qingzhen Huang, Collin L. Broholm, E. Morosan

Abstract

The complex magnetism and transport properties of tetragonal Ce₃Cu₄As₄O₂ were examined through neutron scattering and physical properties measurements on polycrystalline samples. We find a lamellar structure consisting of alternating layers of CeCu₄As₄ with a single square Ce lattice and oxygen-linked Ce bi-layer Ce₂O₂. Extending along c, a tube-like Fermi surface from DFT calculations points to a quasi-two-dimensional electronic system. Peaks in the specific heat at the Neel temperature T_N = 23.5 K and subsequent magnetic transitions at T₂ = 15.8 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, a wave vector K₁=c, and a correlation length in excess of 50 A. For T2, the quasi-two-dimensional low-energy spin fluctuations with K₂ = 1/2A and polarized perpendicular to K₂ are suppressed. The data are consistent with quasi-two-dimensional antiferromagnetic order in the CeCu₄As₄ planes polarized along the k₂ wave vector. T₃ marks a spin-flop transition where the k₁ staggered magnetization switches to in-plane polarization. While the narrow 4f bands lie deep below the Fermi surface, there are significant transport anomalies associated with the transitions; in particular a substantial reduction in resistivity for T2. At T = 100 mK the k₁ modulated staggered moment is 0.85 υB saturation magnetization achieved for H = 7 T at T =2 K. We suggest that the unusual sequence of magnetic transitions may result from competing interactions and anisotropies for the two rare earth sites.

Citation

Physical Review B

Volume

94

Issue

6

Pub Type

Journals

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Keywords

Magnetic materials, Neutron scattering, quantum criticallity, superconductivity.

Citation

Wang, J. , Wu, S. , Qiu, Y. , Rodriguez Rivera, J. , Huang, Q. , Broholm, C. and Morosan, E. (2016), Modulated Magnetism and Anomalous Electronic Transport in Ce₃Cu₄As₄O₂, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918417 (Accessed May 2, 2024)