Unconventional superconductivity arises at the border between the strong coupling regime with local magnetic moments and the weak coupling regime with itinerant electrons, and stems from the physics of criticality that dissects the two. Unveiling the nature of the quasiparticles close to quantum criticality is fundamental to understand the phase diagram of quantum materials. Here, using resonant inelastic x-ray scattering (RIXS) and \({\rm{Fe}}-{{\rm{K}}}_{\beta }\) emission spectroscopy (XES), we visualize the coexistence and evolution of local magnetic moments and collective spin excitations across the superconducting dome in isovalently-doped BaFe\({}_{2}\)(As\({}_{1-x}\)P\({}_{x}\))\({}_{2}\) (0.00 \( \le \) x \(\le 0.52\)). Collective magnetic excitations resolved by RIXS are gradually hardened, whereas XES reveals a strong suppression of the local magnetic moment upon doping. This relationship is captured by an intermediate coupling theory, explicitly accounting for the partially localized and itinerant nature of the electrons in Fe pnictides. Finally, our work identifies a local-itinerant spin fluctuations channel through which the local moments transfer spin excitations to the particle-hole (paramagnons) continuum across the superconducting dome.

非常规的超导电性出现在具有局部磁矩的强耦合状态和具有流动电子的弱耦合状态之间的边界处，并且源于将两者进行剖析的临界物理学。揭示接近量子临界的准粒子的性质是理解量子材料相图的基础。在这里，使用共振非弹性X射线散射（RIXS）和\（{\ rm {Fe}}-{{\ rm {K}}} _ {\ beta} \）发射光谱（XES），我们可以看到共存和等价掺杂BaFe \（{} _ {2} \）（As \（{{} _ {1-x} \） P \（{} _ {x } \））\（{} _ {2} \）（0.00\（\ le \） x \（\ le 0.52 \））。由RIXS解决的集体磁激励逐渐变硬，而XES揭示了掺杂时对局部磁矩的强烈抑制。这种关系是由中间耦合理论所捕获的，它明确地说明了Fe农药中电子的部分局域化和流动性。最后，我们的工作确定了一个局部流动的自旋涨落通道，通过该通道，局部力矩将自旋激发转移到整个超导穹顶的粒子-孔（顺磁子）连续体。