### Abstract

Measurements of the Knight shift of (Formula presented) and the nuclear spin-lattice relaxation rate of (Formula presented), (Formula presented)(1/(Formula presented)), have revealed that (Formula presented)((Formula presented)(Formula presented))(Formula presented)(Formula presented) with (Formula presented) = 40 K consisting of the bi-(Formula presented) layer without the CuO chain is in the underdoped regime with the spin pseudogap, which is evidenced by the significant decrease of (Formula presented)(1/(Formula presented)T) below 120 K far above (Formula presented) and the decrease of the (Formula presented) spin Knight shift upon cooling. Although the disorder is introduced into the adjacent Ca layers to the (Formula presented) plane by the substitution of Lu for Ca sites, the spin-gap behavior is presented not to be masked. From this result, it is suggested that the absence of the spin-gap behavior in (Formula presented)(Formula presented)(Formula presented) is neither due to the disorder introduced into the adjacent LaO layers to the (Formula presented) plane by the substitution of Sr for La sites nor the absence of the CuO chain.

Original language | English |
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Pages (from-to) | 3070-3073 |

Number of pages | 4 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 54 |

Issue number | 5 |

DOIs | |

Publication status | Published - Jan 1 1996 |

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### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

*Physical Review B - Condensed Matter and Materials Physics*,

*54*(5), 3070-3073. https://doi.org/10.1103/PhysRevB.54.3070