Effect of Multiplicity Fluctuation in Cobalt Ions on Crystal Structure, Magnetic and Electrical Properties of NdCoO3 and SmCoO3.

The structural, magnetic, electrical, and dilatation properties of the rare-earth NdCoO3 and SmCoO3 cobaltites were investigated. Their comparative analysis was carried out and the effect of multiplicity fluctuations on physical properties of the studied cobaltites was considered. Correlations between the spin state change of cobalt ions and the temperature dependence anomalies of the lattice parameters, magnetic susceptibility, volume thermal expansion coefficient, and electrical resistance have been revealed. A comparison of the results with well-studied GdCoO3 allows one to single out both the general tendencies inherent in all rare-earth cobaltites taking into account the lanthanide contraction and peculiar properties of the samples containing Nd and Sm.

Microstructure and superconducting properties of high-rate PLD-derived GdBa2Cu3O7-δ coated conductors with BaSnO3 and BaZrO3 pinning centers.

The microstructure of GdBa2Cu3O7-δ based on superconducting tapes with BaSnO3 and BaZrO3 artificial pinning centers formed by high-rate pulse laser deposition in SuperOx Japan was studied by scanning/transmission electron microscopy. The artificial pinning centers have adopted columnar morphology with average diameter of about 8 nm (BaSnO3-doped sample) and 6.5 nm (BaZrO3-doped sample) and density of 500 µm-2 for the both samples. The average length of the BaSnO3 nanocolumns is about two times higher than the BaZrO3 nanocolumns. The angular dependences of critical current in magnetic field up to 1 Tesla at 77 and 65 K have been obtained. The critical current and its anisotropy depend on artificial pinning centers presence and their type. The angular dependence of resistivity in the field up to 9 Tesla was also studied and discussed.