Research on quantum phase transition by a ferromagnetic fluctuation of ruthenates

层状钙钛矿具有多种新颖的物理性质，如自旋三重态超导性和磁性。在本研究中，我们特别关注双层钌酸钙Ca_3Ru_2O_7，以澄清其产生于4d简并t_<2g>轨道的结果现象。令人惊讶的是，当我们用非磁性Ti^<4+>部分代替Ru^<4+>时，我们观察到“金属-绝缘体转变”。我们还发现了该取代体系的一种新的磁输运性质。

Layered perovskite ruthenates show a variety of novel physical properties, for instance, spin-triplet superconductivity and magnetism. In this study, we particularly focused on a bi-layered calcium-ruthenate, Ca_3Ru_2O_7, in order to clarify its fruitful phenomena originating from 4d degenerate t_<2g> orbitals. Surprisingly, we observed "metal-insulator transition" when we partly substitute nonmagnetic Ti^<4+> for Ru^<4+>. We also detected a novel magneto-transport property on this substituted system.