The Crystal Structure and Magnetic Property Studies on Quasi-One-Dimensional Chain System

Abstract

The materials related to Sr4PtO6 type structure have been studied. In the Sr4PtO6 case, SrO6 trigonal prisms and PtO6 octahedra are repeated along crystallographic c-axis as a chain and every chain is separated by Sr cation. The structure in which chains are separated by alkali earth atoms is related to 2H perovskite ABO3 and A3A’BO6 structures. 2H perovskite ABO3 structures consist of face-sharing octahedral chains. A3A’BO6 structures are made up an alternating trigonal prism and octahedral in a chain. These materials are expected to have one-dimention properties due to separated chains by alkali earth atoms. In Ca3Co1-xMnxO6 material, the ferroelectricity results from the inversion symmetry beaking by up-up-down-down magnetic ordering in one-dimension ising chain system. However, sometimes one-dimension structures have three-dimention magnetic properties like Ca3NaRuO6 material. This thesis shows the structure and magnetic properties of 2H-BaMnO3 and Sr3NiPtO6 materials depending on temperature in the one-dimension magnetic chain structure system sperated by alkali earth atoms. The thesis explains why the room-temperature structure of the 2H-BaMnO3 has not been decidied yet by diffraction methods and structure transition appears below 130K. Sr3NiPtO6 material is strong candidate for Large-D system in S=1, one-dimension chain system. Usually, S=1, one-dimension chain system has Haldane gap. However, Large-D system has different energy gap. The thesis explains what is Large-D and why this system is not familiar with us.