Fig. 4: Magnetic excitations of BLCTO in the 120° ordered phase (T < T_N).

a INS data (I(|Q|, ω), arb. units) measured at 1.65 K (= 0.506T_N) with E_i = 10 meV. b–d Corresponding INS cross-sections calculated from LSWT, NLSWT, and Schwinger boson theory. The calculations were conducted with J₁ = 1.55 meV or 1.77 meV, Δ = 0.56, and J₂ = 0. e INS data measured at 1.65 K (= 0.506T_N) with E_i = 6 meV. f–h Equivalent to (b–d), but convoluted with the coverage and instrumental resolution of the data in (e). i–j Measured and calculated energy-dependent INS cross-sections in the low-|Q| region (0.5 \({{{\text{\AA }}}}^{-1}\) < |Q| < 1.5 \({{{\text{\AA }}}}^{-1}\)). The dashed vertical lines in (i, j) denote the one-magnon bandwidth. k, l Single-crystal excitation spectra along high-symmetry directions (I(q,ω), arb. units), calculated by NLSWT and Schwinger boson theory, respectively. m–o, |Q| dependence of the measured (E_i = 6 meV) and calculated INS cross-sections at the energies indicated by the red, purple, and gray arrows in (e, j). Standard deviations of the data points in (i, j) and (m–o) are much smaller than the data symbol. Only the calculation results in panels (a–j) and (m–o) are convoluted with instrumental resolution.