LOW-TEMPERATURE UNIT-CELL PARAMETERS OF LA1-XPRXCABACU3O7 COMPOUNDS

The suppression of the superconductivity by praseodymium in La1-xPrxCaBaCu3O7 may be explained in terms of the difference in the electronic or crystal structure between these compounds. Three compositions with x = 0.0, 0.5, 1.0 were, therefore, investigated by X-ray diffraction in order to determine the unit-cell dimensions at room temperature as well as at lower temperatures down to 5 K. The results showed no considerable changes in the orthorhombic unit-cell dimensions on decreasing the temperature to 5 K. Unit-cell volumes at low temperatures were 0.99 of the room temperature values. The intensity sequence of reflections in the diffraction pattern was the same for all samples throughout the range of temperature studied.