Magnetic excitations in the spin-stripe phases of La-based 214-nickelates have been vigorously explored using inelastic neutron scattering study for almost last three decades and still have remained an exciting research field, especially to understand their differences yet of their structural similarities with high-Tc 214-cuprates. In view of so far reported two-dimensional antiferromagnetic nature, out-of-plane magnetic excitations are generally not expected in 214-nickelates. In this talk, I will present our recent results from inelastic neutron scattering measurements on stripe discommensurated phases of Sr-doped Pr3/2Sr1/2NiO4, showing very compelling evidence for the presence of a sizable out-of-plane interaction (Jperp~2.2 meV) which has been crucial to explain the measured magnetic excitations in Pr3/2Sr1/2NiO4 . Our results suggest ubiquitous presence of anisotropic three-dimensional nature of magnetic excitations near the half-doped region of Pr3/2Sr1/2NiO4 . The measured magnetic excitations are in good accordance with our linear spin wave theory based calculations in the discommensurated spin stripe units. Additionally, I will discuss the effect of short-range vs. long-range spin correlations on the spin wave dispersion by comparing our inelastic neutron scattering study of magnetic excitation of an oxygen-doped sample Pr2NiO4+δ .
 A. Maity et al., Phys. Rev. Lett. 124, 147202 (2020).
 R. Dutta et al., Phys. Rev. B 102, 165130 (2020).
 A. Maity et al., Phys. Rev. B 103, L100401 (2021).
Dr. Jitae Park
Dr. Theresia Heiden-Hecht
Dr. Dominic Hayward