SUPERCONDUCTING STATE OF THE LAYERED RUTHENATE

The objective of research project is to clarify the superconducting symmetry of Sr I D22文件D2 RuO I D 24文件D2 mainly through investigation of the specific heat and nuclear magnetic resonance.Through this research project，the quality of the single crystals of Sr I D22 I D 2 RuO I D 24 I D 2 has reached an ideal level for most of the investigations.1.As a major achievement of this project，we have demonstrated by nuclear magnetic resonance that superconductivity of Sr I D22文件D2 RuO文件D24文件D2 is spin triplet.2。We have also provided our crystals to many collaborators，who reported a number of important results。In particular，the observation of spontaneous internal field in the superconducting state by muon spin relaxation indicated that the time-reversal-symmetry is spontaneously broken in the superconducting state，another crucial characteristics of the spin-triplet state specific to Sri D22 Ieously broken in the superconducting state，another crucial characteristics of the spin-triplet state specific to Sri D22 Ii D2 RuO Ii D24 I D2.3。In addition，we have succeeded in inducing superconducting multiple phases under magnetic fields，characteristic of spin-triplet supcrconductivity.4。Furthermore，we found that the superconducting transition temperature enhances by a factor of two to3K in a eutectic mixture of Sr I D22文件D2RuO文件D24文件D2 and Ru metal.5。At the same time，detailed theoretical models have been developed in order to describe both the superconducting symmetry and the pairing mechanism of Sr I D22 I D 2 RuO I D 24 ii D 2.

The objective of research project is to clarify the superconducting symmetry of SrィイD22ィエD2RuOィイD24ィエD2 mainly through investigation of the specific heat and nuclear magnetic resonance. Through this research project, the quality of the single crystals of SrィイD22ィエD2RuOィイD24ィエD2 has reached an ideal level for most of the investigations.1. As a major achievement of this project, we have demonstrated by nuclear magnetic resonance that superconductivity of SrィイD22ィエD2RuOィイD24ィエD2 is spin triplet.2. We have also provided our crystals to many collaborators, who reported a number of important results. In particular, the observation of spontaneous internal field in the superconducting state by muon spin relaxation indicated that the time-reversal-symmetry is spontaneously broken in the superconducting state, another crucial characteristics of the spin-triplet state specific to SrィイD22ィエD2RuOィイD24ィエD2.3. In addition, we have succeeded in inducing superconducting multiple phases under magnetic fields, characteristic of spin-triplet supcrconductivity.4. Furthermore, we found that the superconducting transition temperature enhances by a factor of two to 3 K in a eutectic mixture of SrィイD22ィエD2RuOィイD24ィエD2 and Ru metal.5. At the same time, detailed theoretical models have been developed in order to describe both the superconducting symmetry and the pairing mechanism of SrィイD22ィエD2RuOィイD24ィエD2.