0000000000598789
AUTHOR
N. Sparvieri
Thermal diffusivity measurements for Mg-Mn ferrites
Abstract The thermal diffusivity of Mg-Mn ferrites is studied through a modified scheme of the photothermal deflection method able to derive the diffusivity of low-diffusivity samples and to avoid any influence of the vertical offset parameter. The examined samples have been realized under different preparation conditions producing different grain dimensions, and a negligible influence of the grain dimensions is found on the thermal properties.
Superconducting properties of polycrystalline YBCO prepared by a pyrolytic process
Polycrystalline YBCO was prepared by a pyrolytic process starting from citrate and tartrate precursors. The effect of the precursor on the superconducting properties was investigated by means of magnetic measurements using a SQUID magnetometer, a Vibrating-Sample Magnetometer and an a.c. susceptometer. The critical temperature is not affected by the type of precursor (Tc=85 K for both). On the other hand, the precursor plays an important role on the critical current density, which is found to be an order of magnitude higher in the sample obtained from citrates (Jc(77K, H=0)=2.3·104 A/cm2 and 103 A/cm2 for the from-citrate and from-tartrate sample, respectively).