Lanthanum cuprate usually refers to the inorganic compound with the formula CuLa2O4. The name implies that the compound consists of a cuprate (CuOn]2n-) salt of lanthanum (La3+). In fact it is a highly covalent solid. It is prepared by high temperature reaction of lanthanum oxide and copper(II) oxide follow by annealing under oxygen.
The material adopts a tetragonal structure related to potassium tetrafluoronickelate (K2NiF4), which is orthorhombic.[1] [2] Replacement of some lanthanum by barium gives the quaternary phase CuLa1.85Ba0.15O4, called lanthanum barium copper oxide. That doped material displays superconductivity at, which at the time of its discovery was a high temperature. This discovery initiated research on cuprate superconductors and was the basis of a Nobel Prize in Physics to Georg Bednorz and K. Alex Müller.[3]