Electronic states of alkali-doped CィイD260ィエD2 compounds : a NMR study

A systematic study of alkali-doped C i D260个D 2compounds，A个D 23个D 2C个D 260个D 2where A is a alkali metal，has been performed to clarify the electronic states，using nuclear magnetic resonance(NMR)technique.Main results are summarized as follows.1。The I D 113 I D 1 C-heperfine coupling constants have been determined in the superconducting A I D 23 I D 2 C I D 260 I D 2.At，low temperatures(&lt；100K)，the enhancement of Korringa product，has been determined，which shows a weak antiferromagnetic correlation.3。Rising temperature and increasing lattice constant，the enhancement of Korringa product，increases。This was at atributed to the short electron mean free path in this system.4。Ammoniated A I D23个D 2C个D 260个D 2superconductors with expanded lattice constants show a“gap”-like behavior in the temperature dependence of spin-lattice relaxation time T I D 21个D 2.5。It was shown that(NH3)K3C60is described as a localized spin system in whole temperature studied(&lt；300K)and undergoes an antiferromagnetic transition at45K.6。From these results，it was strongly suggested that the metallic state of A I D23个D 2C个D 260个D 2is unstable to the local distortion around C个D 260个D 2molecules.

A systematic study of alkali-doped CィイD260ィエD2 compounds, AィイD23ィエD2CィイD260ィエD2 where A is a alkali metal, has been performed to clarify the electronic states, using nuclear magnetic resonance (NMR) technique. Main results are summarized as follows.1. The ィイD113ィエD1C-heperfine coupling constants have been determined in the superconducting AィイD23ィエD2CィイD260ィエD2.2. At, low temperatures (<100K), the enhancement of Korringa product, has been determined, which shows a weak antiferromagnetic correlation.3. Rising temperature and increasing lattice constant, the enhancement of Korringa product, increases. This was at atributed to the short electron mean free path in this system.4. Ammoniated AィイD23ィエD2CィイD260ィエD2 superconductors with expanded lattice constants show a "gap"-like behavior in the temperature dependence of spin-lattice relaxation time TィイD21ィエD2.5. It was shown that (NH3)K3C60 is described as a localized spin system in whole temperature studied (<300 K) and undergoes an antiferromagnetic transition at 45 K.6. From these results, it was strongly suggested that the metallic state of AィイD23ィエD2CィイD260ィエD2 is unstable to the local distortion around CィイD260ィエD2 molecules.