Abnormal structural behavior of Y0.8Ca0.2Ba1.8Nd0.2Cu3Oy at low temperature

The variation of structure and transport property for the nominal compositi on of Y0.8Ca0.2. Ba1.8NdCu3Oy (YCBNC) at temperature range of 78 K < T < 28 4 K were studied. YCBNC shows a superconducting transition temperature (zer o resistivity) of T-c0 similar to 83 K. There is no phase transition detect ed in the accuracy of our experiments in the whole temperature range. The d ependences of lattice constants upon temperature can be discussed in two te mperature regions. The other atomic parameters, or the deduced structural p arameters, such as the orthorhombic strain, the lattice strain, some select ed bond lengths and bond angles all depend on temperature. The dependences of the atomic structural parameters on temperature indicate that these atom ic structural parameters may relate to the superconductivity to some extent .