We have successfully synthesized polycrystalline bulk samples of La 2CuO4 with the Nd2CuO4-type (T′) structure at low temperatures. First of all, La2CuO 4 with the K2NiF4-type (T) structure was prepared by the conventional solid-state reaction. Secondly, La 2CuO3.5+δ with the Sr2CuO 3-type structure was obtained by heating mixed powder of T-La 2CuO4 and CaH2 at 175 °C in an evacuated Pyrex tube. Thirdly, T′-La2CuO4+δ was prepared by heating La2CuO3.5+δ at 250 °C in air. Finally, T′-La2CuO4+ δ was reduced using CaH2 to remove excess oxygen. The powder X-ray diffraction pattern has revealed that the product is of the single phase of T′-La2CuO4, but no superconductivity has been observed at T > 2 K in the magnetic susceptibility measurement. The residual excess oxygen may suppress the appearance of superconductivity.
- Low-temperature synthesis
ASJC Scopus subject areas
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Energy Engineering and Power Technology
- Electronic, Optical and Magnetic Materials