Fig. 2: The collective spin fluctuations in Sr3Ru2O7 measured through its quantum critical point.
From: Magnetic-field-controlled spin fluctuations and quantum criticality in Sr3Ru2O7
a–f Energy-dependent spectra of the magnetic response function χ″(Q, ω) for Q = Qδ measured for magnetic fields through the critical field. The magnetic response has a Lorentzian form (solid lines) and softens (strengthens at the lowest energies) for the critical field Bc = 7.95 T. The data have been integrated over −0.5 < ℓ < 0.5. Colour of points indicates the incident neutron energy (Ei), also in Fig. 1. g The wavevector-dependent susceptibility χδ is peaked at Bc. h The spin relaxation rate Γδ is minimum at Bc and the inset shows that the relaxation time τ = 1/Γδ ∝ χδ. j The spin fluctuations are seen at Q = (1 − δ, 0, 0) and not at (1, δ, 0) implying that they have transverse polarisation as illustrated for the SDW propagating along the a-axis.
