Recently, a striking positive effect of tiny Zn doping on crystal growth quality has been found in melt-textured (Nd, Eu, Gd)Ba_2Cu_3O_y pellets. The material could be easily grown from MgO seed, possessing a rather high lattice mismatch to the superconducting compound. In the present work we study spatial distribution of local magnetic properties and chemical composition of a (Nd_{0.33}Eu_{0.38}Gd_{0.28})Ba_2Cu_3O_y + 0.035 mol% Zn pellet. The plane cutting the pellet into two halves along the symmetry axes of the opposite a-axis growth sectors is investigated. While the chemical composition only slightly fluctuates, magnetic properties show quite an interesting spatial variation.
Specific heat of superconducting electrons was measured in a melt-processed (Nd_{0.33}Eu_{0.38}Gd_{0.28})Ba_2Cu_3O_{y} superconductor (NEG-123) with 5 mol% of Gd-211, 1 wt% Ag, and 0.035 mol% of Zn. The thermodynamic characteristics of this compound are still not well known. From calorimetric measurements the reversible magnetization, critical fields, penetration depth, and coherence length were deduced. In the vicinity of T_{c}, the reversible magnetic moment was additionally measured by means of SQUID.
Electromagnetic properties of YBa_{2}Cu_{3}O_{y} samples melt-grown in air and doped with small amounts of light rare earth (LRE) ions Gd and Sm were studied. The LRE doping creates a point-like disorder contributing to the second peak on the magnetization curve. In the field range of the second peak the average magnetic moment, M_{av}, deduced from the magnetization curves exhibited strong fluctuations. M_{av} is commonly regarded as an equilibrium moment close to the thermodynamic reversible one, obeying in intermediate fields a logarithmic field dependence. However, in our experiments M_{av}(B) curves failed to follow such a dependence below irreversibility line. M_{av}(B) curves deduced from rather static measurements, done by SQUID magnetometer still showed the disturbance but significantly weaker. It indicates that this feature reflects the vortex dynamics in the second peak region. Its scaling with temperature was found to coincide with that of the pinning force.