Neutron scattering study on CeAgAs2 |
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Authors: | Th. Doert,A. Schneidewind,M. Hö lzel,O. StockertD. Rutzinger,M. Ruck |
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Affiliation: | a Fachrichtung Chemie und Lebensmittelchemie, Technische Universität Dresden, D-01062 Dresden, Germany b Forschungsneutronenquelle Heinz Maier-Leibniz (FRM-II), Technische Universität München, Lichtenbergstr. 1, D-85748 Garching, Germany c Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany d Fachbereich Material- und Geowissenschaften, Technische Universität Darmstadt, D-64287 Darmstadt, Germany e Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Str. 40, D-01187 Dresden, Germany |
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Abstract: | CeAgAs2, an HfCuSi2 like layered pnictide, orders antiferromagnetically at TN=6.2(1) K. The ordering process was monitored in neutron diffraction experiments in the temperature range 10 K≥T≥3.5 K. At T=4 K the lattice parameters are a=5.7438(1) Å, b=5.7696(1) Å and c=21.0067(2) Å. The diffraction pattern of the antiferromagnetic phase with a propagation vector k=[0,0,0] point towards ferromagnetically ordered moments in Ce layers stacked along [001], the individual layers are coupled antiferromagnetically with a +− −+type sequence. The alignment of moments within the Ce layers cannot be determined reliably from the experimental data so that two different structure models are discussed. The proposed metamagnetic transition was confirmed by diffraction experiments applying an external magnetic field at T<TN. In the interval 4 K≤T≤6 K, a relatively small field of μ0H≈0.3 T suffices to fully suppress the antiferromagnetic ordering. The effect is completely reversible yet subject to hysteresis: After switching off the external field at any T<TN the magnetic reflections gain their original intensity within several 10 min indicating the restoring of the antiferromagnetic phase. |
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Keywords: | CeAgAs2 Neutron diffraction Magnetic structure Metamagnetic transition |
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