Thermal expansion of the high-7c superconductors REBa2Cu3O7 (RE = Y, Dy) revisited at low temperatures

11th European Conference on Applied Superconductivity

Lahoubi, M.^1

Badji Mokhtar-Annaba University, Faculty of Sciences, Department of Physics, PO Box 12, Annaba

23000, Algeria^1

关键词: Electric quadrupole moment;    High Tc superconductors;    Linear thermal expansion coefficients;    Magnetic contribution;    Micro-structural characterization;    Polycrystalline samples;    Rising temperatures;    Temperature range;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012028/pdf
DOI  :  10.1088/1742-6596/507/1/012028

来源: IOP

【 摘 要 】

The linear thermal expansion coefficient α(T) of two high-Tcsuperconductors, YBa2Cu3O7and DyBa2Cu3O7has been revisited in the 4.5-80K temperature range. The X-ray diffraction analysis and microstructural characterization using scanning electron microscopy confirm an orthorhombic single phase with an average of the grain size of about 20 μm for both polycrystalline samples. In the case of the Dy compound, a small magnetic excess superimposed to the high phonon contribution is observed in the T3term, whereas no anomaly is detected below 40K. The deduced magnetic contribution αm(T) which increases monotonically with rising temperature is attributed to the CF interactions induced by the 4f electric quadrupole moment of the Dy Kramers ions. A discussion and a comparison with respect to the previous experimental and theoretical works are presented.