### Abstract

Structural, magnetic, and calorimetric studies have been made to reveal an anomalous Pr antiferromagnetic ordering at (Formula presented)(Pr) of 6 K in (Formula presented)(Formula presented)(Formula presented). This compound has the Hg-1212-type tetragonal structure with lattice parameters a=3.8532 Å and c=12.1199 Å. X-ray Rietveld refinement yields a Pr-O bond length d(Pr-O) of 2.492 Å between Pr and oxygen in the adjacent (Formula presented) layers and an O-Pr-O bond angle of 101.3°. The low-temperature magnetic entropy associated with the Pr ordering is only about 10% of Rln3 expected for (Formula presented) with a quasitriplet ground state, suggesting a more two-dimensional-like ordering process. This result supports the earlier observation of a systematic dependence of (Formula presented)(Pr) on Pr-O bond length in various M(Ba, Sr(Formula presented)(Formula presented)(Formula presented) (M=Cu, Hg, Tl, Pb) 1212-type Pr compounds. This in turn points to the importance of a superexchange magnetic coupling mechanism.

Original language | English |
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Pages (from-to) | 6729-6733 |

Number of pages | 5 |

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

Volume | 53 |

Issue number | 10 |

DOIs | |

Publication status | Published - 1996 Jan 1 |

Externally published | Yes |

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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*,

*53*(10), 6729-6733. https://doi.org/10.1103/PhysRevB.53.6729