IISER MOHALI

Abstract: Studies of spatially inhomogeneous charge and spin stripe correlations and their dynamics in the hole-doped La based 214-nickelates remain an interesting field of investigation in the last three decades, especially to understand the role of stripe correlations and fluctuations in high-Tc superconductivity observed in the isostructural cuprates. In this talk, I will present our recent studies on the charge and spin stripe correlations and magnetic excitations on a series of hole-doped Pr based 214-nickelates using single crystal synchrotron diffraction and inelastic neutron scattering (INS) studies. Our INS results on the stripe discommensurated phases of Sr-doped samples Pr3/2Sr1/2NiO4 show compelling evidence for the presence of sizable out-of-plane interactions among the Ni2+ ions presenting an anisotropic three-dimensional nature of magnetic excitations, which has not been reported so far in La based 214-nickelates considering their two-dimensional nature of magnetic excitations. Additionally, to extract the exchange interactions among the Ni2+ ions and simulate the magnetic excitations, we have performed linear spin wave calculations in an unconventional (discommensurated) spin stripe unit, which presents an excellent agreement with the measured magnetic excitations. In addition to the Sr-doped samples, I will also discuss our INS studies on O-doped samples Pr2NiO4+δ, which reveals multiple equivalent modes in the magnetic excitations that has not been reported earlier in 214-Nickelates. We relate such observation of multiple modes to the long-range nature of spin stripe ordering, established in the same length scale of interstitial oxygen ordering in the O-doped samples Pr2NiO4+δ.\n\nReferences: \nA. Maity et al., Phys. Rev. Lett. 124, 147202 (2020).\nR. Dutta, A. Maity et al., Phys. Rev. B 102, 165130 (2020).\nA. Maity et al., Phys. Rev. B 103, L100401 (2021).\nR. Dutta, A. Maity et al., Phys. Rev. B 105, 195147 (2022).\nA. Maity et al., Phys. Rev. B 106, 024414 (2022).\n\nMeeting ID: 988 1664 6059\nPasscode: 276875\n