Frustrated Magnetic Interactions and Quenched Spin Fluctuations in CrAs

Published

November 1, 2022

Author(s)

Yayuan Qin, Yao Shen, Yiqing Hao, Hongliang Wo, Shoudong Shen, Russell A. Ewings, Yang Zhao, Leland Harriger, Jeffrey Lynn, Jun Zhao

Abstract

The discovery of pressure-induced superconductivity in helimagnets (CrAs, MnP) has attracted significant interest in understanding the relationship between complex magnetism and unconventional superconductivity. However, the nature of the magnetism and magnetic interactions that drive the unusual double-helical magnetic order in these materials remain unclear. Here, we report neutron scattering measurements of magnetic excitations in CrAs single crystals at ambient pressure. Our experiments reveal well defined spin wave excitations up to ∼150 meV at 8 K, which can be effectively described by the Heisenberg model with highly frustrated nearest neighbored exchange interactions. In contrast to the clean spin gap commonly observed in cuprates and iron pnictides, CrAs shows a pseudogap behavior below 7 meV, exhibiting unique spin excitations associated with the helical order and easy-plane anisotropy. The pseudogap softens on warming and the spin waves are eventually replaced by short-range correlated incommensurate spin fluctuations above the N´eel temperature. Our results highlight the localized characteristics of the frustrated magnetism in CrAs and suggest that electronic correlations significantly influence its physical properties.

Citation

Chinese Physics Letters

Volume

39

Issue

12

Pub Type

Journals

Download Paper

DOI Link

Keywords

Spin Dynamics, Superconductivity, Pressure, Frustrated Magnetism, Antiferromagnetic order, CrAs

Citation

Qin, Y. , Shen, Y. , Hao, Y. , Wo, H. , Shen, S. , Ewings, R. , Zhao, Y. , Harriger, L. , Lynn, J. and Zhao, J. (2022), Frustrated Magnetic Interactions and Quenched Spin Fluctuations in CrAs, Chinese Physics Letters, [online], https://dx.doi.org/10.1088/0256-307X/39/12/127501 (Accessed April 28, 2024)