Orthorhombic kagome cobaltite CaBaCo4O7: A new ferrimagnet with a T-C of 70 K

摘要

A novel mixed valent cobaltite CaBaCo4O7 has been synthesized. Its structure, closely related to the LnBaCo(4)O(7) oxides of the "114" series, differs from the latter by a large orthorhombic distortion, involving a buckling of the CoO4 tetrahedra of the kagome layers. Importantly, this new phase is ferrimagnetic with a T-C = 70 K and a very large coercive field of 2 T at 5 K, in contrast to LnBaCo(4)O(7) oxides, which exhibit magnetic frustration.