Study of effect of Sn doping of EuBa2Cu3-xO7-δ compound on superconducting properties by contactless methods

Effect of Sn addition on structural and superconducting properties in EuBa2Cu3O7-δ (Eu-123) compound was studied using XRD and SQUID magnetometric measurements. Transition process from normal to superconducting state was analyzed by the measurement of temperature change of the magnetic moment of the combined ZFC and the remanence technique beside the usual ZFC and FC ones. Samples of the nominal composition EuBa2Cu3-xSnxO7-δ with x ranging from 0.0 to 0.2 were prepared by the solid state reaction technique from Eu2O3, BaCO3, CuO and SnO2 precursors. The increasing Sn-content deteriorates the superconducting properties of the Sn doped samples

Model dependence of single-energy fits to pion photoproduction data

Model dependence of multipole analysis has been explored through energy-dependent and single-energy fits to pion photoproduction data. The MAID energy-dependent solution has been used as input for an event generator producing realistic pseudo data. These were fitted using the SAID parametrization approach to determine single-energy and energy-dependent solutions over a range of lab photon energies from 200 to 1200 MeV. The resulting solutions were found to be consistent with the input amplitudes from MAID. Fits with a $\chi$-squared per datum of unity or less were generally achieved. We discuss energy regions where consistent results are expected, and explore the sensitivity of fits to the number of included single- and double-polarization observables. The influence of Watson's theorem is examined in detail.Comment: 12 pages, 8 figure

Nucleon charge exchange on the deuteron: A critical review

The existing experimental data on the d(n,p)nn and d(p,n)pp cross sections in the forward direction are reviewed in terms of the Dean sum rule. It is shown that the measurement of the ratio of the charge exchange on the deuteron to that on the proton might, if taken together with other experimental data, allow a direct construction of the np -> np scattering amplitude in the backward direction with few ambiguities.Comment: 7 pages with 3 figure

Philosophy of law in the Soviet Union and the people’s democracies

The fate of Marxism in the Soviet Union and the people’s democracies as the former’s extension owing to post-WWII occupation was from the beginning sealed by Bolshevism, that is, the politico-ideological domination and use of the scholarly domain as well, made to self-close in a merely justificatory role. There may have been attempts at opening, even if only conceivable within—i.e. preserving at the same time—this framework function. In the present conspectus, the limiting positions are occupied by the Soviet Union and the German Democratic Republic, completed by after-1968 Czechoslovakia, as well as Yugoslavia and pre-1968 Czechoslovakia, representing the substitute-to-religion dogmatic side, exclusively politically motivated in the former and subordinated to a humanising tendency in the latter case, on the one hand, and Poland, dedicated to a purely analytical approach, in which Marxism has simply no relevance, on the other. Hungary, treated in an earlier paper by the author, was in-between, taking Marxism seriously but mostly as a methodology, and thereby able to foster live debates. All that notwithstanding, there has been quite a few progressive moves also in Romania and Bulgaria in this specific academic field. Turning topoi of the discussions were, chronologically but recurrent transubstantiatedly, the exclusivity of Vyshinsky’s socialist normativism, the consequences ensuing from the law’s superstructural nature, the discontinuity vs. continuity of law in historical development, and, in the background, the dilemma of the ontological/epistemological understanding of Marxism, the latter standing for a rigid Leninist reducibility of law to its material substratum as the product of sheer reflection, and the former enabling to develop the law’s relative autonomy as in Lukács’ posthumous ontology. On the final analysis, all these forced paths made a whole region’s efforts to be belated as compared to international developments, the fact notwithstanding those outstanding achievements were born especially on the fields of legal ontology and sociology, as well as the legal methodology and particularly that of the comparison of laws

Effects of Gd/Ba Nonstoichiometry in Gd1+xBa2−xCu3O7−δGd_{1+x}Ba_{2-x}Cu_{3}O_{7-δ} on Superconducting and Magnetic Properties

Effects of slight nonstoichiometry in $Gd_{1+x}Ba_{2-x}Cu_{3}O_{7-δ}$ compounds on superconducting and magnetic properties were studied. The series of single-phase samples of $Gd_{1+x}Ba_{2-x}Cu_{3}O_{7-δ}$ with composition deviation x from the stoichiometric value of 0 to 0.1 and to -0.1 were synthesized by the solid-state reaction method from $Gd_{2}O_{3}$, $BaCO_{3}$ and CuO precursors, sintered at the temperature of ~ 1000°C in flowing oxygen and annealed at 450°C for 24 h

Magnetic Studies of EuBa2Cu3−xRuxO7−δEuBa₂Cu_{3-x}RuₓO_{7-δ} Compounds

Effects of Ru addition on magnetic properties of $EuBa₂Cu_{3-x}RuₓO_{7-δ}$ compounds were studied. Samples of $EuBa₂Cu_{3-x}RuₓO_{7-δ}$ with x from 0.00 to 0.70 were prepared by the solid state reaction technique from Eu₂O₃, BaCO₃, CuO and RuO₂ precursors. Temperature dependences of the zero-field cooled (ZFC) and the field cooled (FC) DC magnetic moment at low and high applied magnetic field Hₐ were measured by the QD SQUID magnetometer MPMS XL-7 and AC magnetization $M_{AC}(H)$ curves at 77 K by the compensation method using the second-order SQUID gradiometer. The molar susceptibility χ of the samples was corrected to the effects of the sample holder and diamagnetism and χ* also was corrected to the temperature independent paramagnetic/diamagnetic contribution $χ^{TN}$ and fitted by the Curie-Weiss relation. The values of the Weiss temperature and the effective magnetic moment have been estimated at low and high value of applied magnetic field