Spin fluctuations in the 112-type iron-based superconductor Ca0.82La0.18Fe0.96Ni0.04As2

Tao Xie; Chang Liu; Ryoichi Kajimoto; Kazuhiko Ikeuchi; Shiliang Li; Huiqian Luo

doi:10.1088/1361-648X/ac9441

Spin fluctuations in the 112-type iron-based superconductor Ca_0.82La_0.18Fe_0.96Ni_0.04As₂

J Phys Condens Matter. 2022 Sep 29;34(47). doi: 10.1088/1361-648X/ac9441.

Authors

Tao Xie^{1

2

3}, Chang Liu^{1

2}, Ryoichi Kajimoto⁴, Kazuhiko Ikeuchi⁵, Shiliang Li^{1

2

6}, Huiqian Luo^{1

6}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
² School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
³ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America.
⁴ Materials and Life Science Division, J-PARC Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan.
⁵ Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society, Tokai, Ibaraki 319-1106, Japan.
⁶ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China.

PMID: 36137515
DOI: 10.1088/1361-648X/ac9441

Abstract

We report time-of-flight inelastic neutron scattering (INS) investigations on the spin fluctuation spectrum in the 112-type iron-based superconductor (FeSC) Ca_0.82La_0.18Fe_0.96Ni_0.04As₂(CaLa-112). In comparison to the 122-type FeSCs with a centrosymmetric tetragonal lattice structure (space groupI4/mmm) at room temperature and an in-plane stripe-type antiferromagnetic (AF) order at low temperature, the 112 system has a noncentrosymmetric structure (space groupP21) with additional zigzag arsenic chains between Ca/La layers and a magnetic ground state with similar wavevectorQAFbut different orientations of ordered moments in the parent compounds. Our INS study clearly reveals that the in-plane dispersions and the bandwidth of spin excitations in the superconducting CaLa-112 closely resemble to those in 122 systems. While the total fluctuating moments⟨m2⟩≈4.6±0.2μB2/Fe are larger than 122 system, the dynamic correlation lengths are similar (ξ ≈ 10 Å). These results suggest that superconductivity in iron arsenides may have a common magnetic origin under similar magnetic exchange couplings with a dual nature from local moments and itinerant electrons, despite their different magnetic patterns and lattice symmetries.

Keywords: inelastic neutron scattering; iron-based superconductors; spin excitations.

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