57Fe-doped and undoped single crystals were grown for Mössbauer and magnetic AC susceptibility measurements. The effects of cooling rate and the concentration of the YBa2(Cu1-x57Fex)3O7-δ-powder in the melt were examined. The lattice parameters of the single crystals were determined by x-ray diffraction. Growth in air yielded orthorhombic crystals with a- and b-axes differing only slightly and having Tc=77K for undoped and 57 K for 57Fe-doped crystals. Mössbauer spectra indicated the presence of regions with different oxygen contents.
|Tidskrift||Physica C: Superconductivity and its Applications|
|Status||Publicerad - dec. 1989|