Observation of spin-glass like behavior in the layered oxyselenides La(2)O(3)(Mn(1−x)Co(x))(2)Se(2)

We have synthesized a new series of layered oxyselenides La(2)O(3)(Mn(1−x)Co(x))(2)Se(2) through a solid state reaction method. Their structure and physical properties were studied through powder X-ray diffraction, electric transport measurements, absorption spectroscopy, bulk magnetization and specific heat experiments. These compounds crystallize in layered structures with the space group I4/mmm. All the samples present semiconducting or insulating behavior with the activation energy ranging from 0.134 eV to 0.400 eV. The ferromagnetic (FM) component is induced as Co enters the lattice, and the FM component raises to its maximum when x is 0.6. The competing of FM and antiferromagnetic (AFM) components led to the emergence of a spin-glass like behavior in the intermediate alloys.