Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 54: Correlated Electrons: Complex Oxides and Other Materials
TT 54.7: Talk
Thursday, April 4, 2019, 11:15–11:30, H22
Raman spectroscopy study of the lattice and spin dynamics in CrAs — •Yi Yao1, Matthieu Le Tacon1, Kaushik Sen1, Michaela Souliou1, Amir-Abbas Haghighirad1, Michael Merz1, Christoph Meingast1, Frederic Hardy1, Anahita Omoumi2, Measson Marie-Aude3, and Pawbake Amit3 — 1Karlsruhe Institute of Technology, Institute for Solid State Physics — 2University Paris Sud — 3Institut Néel, Magnetic and superconductivity group
We performed Raman measurements to probe the lattice and spin dynamics of high quality single crystals of CrAs, an antiferromagnetic (AFM) double-helical system that becomes superconducting under pressure[1]. The samples were grown using a flux method, and characterized using XRD and magnetic susceptibility measurements. At the AFM ordering temperature TN = 265 K, below which helical AFM order sets in, the sample exhibits a strong first order structural transition, upon which the lattice parameter b expands by ≈ 3.39%. In the Raman experiments, four Raman active modes with Ag symmetry were observed, as predicted from group theory. All these modes exhibit pronounced anomalies in their frequencies and linewidths across TN. In addition, we found a signature of magnon scattering, and signatures of spin-phonon coupling are discussed. Finally, our high-pressure Raman experiments show the suppression of TN under hydrostatic compression, in agreement with previous studies[1,2].
W. Wei. et al., Nature Comm. 5 (2014)
Y. Shen. et al., Phys. Rev. B 93 (2016)