Spin fluctuations in the 112-type iron-based superconductor Ca
La
Fe
Ni
As
112型鉄系超伝導体Ca
La
Fe
Ni
As
におけるスピン揺らぎ
Xie, T.*; Liu, C.*; 梶本 亮一
; 池内 和彦*; Li, S.*; Luo, H.*
Xie, T.*; Liu, C.*; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Li, S.*; Luo, H.*
We report time-of-flight inelastic neutron scattering (INS) investigations on the spin fluctuation spectrum in the 112-type iron-based superconductor (FeSC) Ca
La
Fe
Ni
As
(CaLa-112). In comparison to the 122-type FeSCs with a centrosymmetric tetragonal lattice structure (space group
) at room temperature and an in-plane stripe-type antiferromagnetic (AF) order at low temperature, the 112 system has a noncentrosymmetric structure (space group
) with additional zigzag arsenic chains between Ca/La layers and a magnetic ground state with similar wavevector
but 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
/Fe are larger than 122 system, the dynamic correlation lengths are similar (
). 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.