Magnetic and crystal structures of BaCoCaRuO

Horie, Akihiro*; Yasui, Yukio*; Igarashi, Taichi*; Yatagai, Ryo*; Yamamoto, Takafumi*; Terasaki, Ichiro*; Matsukawa, Takeshi*; Hoshikawa, Akinori*; Ishigaki, Toru*; Igawa, Naoki

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The magnetic and crystal structures, and magnetic properties of BaCoCaRuO have been studied by using the neutron powder diffraction and the magnetization analysis. With increasing , an antiferromagnetic transition temperature decreases such as = 88 K (=0.1), 82 K (=0.2), and 76 K (=0.3), respectively. We have observed magnetic reflections, which can not be explained by the collinear structure. Though the lattice volume increases, we have found that a Ru-Ru bond length decreases with increasing . It is considered to be related with the Ru-Ru dimerization. By the combined studies of the magnetic properties and neutron diffraction analysis, we will discuss the change of Ru-spins with varying .