沙漏状磁激发是铜基高温超导体中非常常见的一种现象，许多研究表明其与超导配对机制具有紧密的联系，但是其微观机理却仍然存在诸多争议。最近在与层状铜氧化物La2-xSrxCuO4同构但绝缘的钴氧化物La2-xSrxCoO4当中同样发现了沙漏状的磁激发吸引了国际同行的广泛兴趣。虽然其绝缘性可以排除费米面效应的影响，但根本原因仍有争议。本项目创新性地通过氧过量实现空穴掺杂，减少对母体晶体结构的影响，采用中子散射、缪子自旋弛豫等手段对其电荷有序、磁有序以及磁激发进行研究，我们将完成对La2CoO4+d体系空穴浓度-温度相图的研究，并阐明在La2-xSrxCoO4体系当中仍未解决的问题，即到底是纳米相分离还是电荷条纹相造成了沙漏状磁激发？最终为理解铜基高温超导体中的磁激发行为提供新的方向。

Hourglass shaped magnetic excitation is a universal property observed in the high temperature superconducting cuprate (HTSC). Numerous studies have demonstrated that it is closely related to the superconducting pairing mechanism. However, its detailed microscopic origin is still under intense debates. Recently, hourglass shaped magnetic excitations have also been observed in the layered cobalt oxide La2-xSrxCoO4, which is isostructural to the HTSC La2-xSrxCuO4. This observation has stimulated much research interest amongst the international community. The insulating nature in La2-xSrxCoO4 rules out the Fermi surface effect. However, it is still controversial if the charge stripe ordering or the nano phase separation plays a key role for the observed hourglass shaped excitations. In this project, we focus on the La2CoO4+d system, in which the hole doping is realized by introducing excess oxygen at the intermediate sites. Oxygen doping has less influence on the crystal structure of the parent compound compared to the Sr doping. We aim to study the charge order, magnetic order and magnetic excitations within the hole-temperature phase diagram of La2CoO4+d, and elucidate whether nano phase separation or charge stripe ordering is responsible for the hourglass shaped magnetic excitations. These results will eventually provide new insights for the pairing mechanism for the HTSC.