摘要
The effects of the incorporation of Pr atoms onto the Ba sites on the structural and magnetic properties of Pr 1+x Ba 2-x Cu 3 O 7+y , with x=0.22 and 0.48, were studied by using neutron diffraction and ac magnetic susceptibility measurements. Rietveld structural analysis shows that extra O atoms are pulled into the antichain sites, driving a structural change from an orthorhombic Pmmm to a tetragonal P4/mmm symmetry, when the chain and antichain sites become equally populated. Significant reductions in the ordering temperature of the Pr spins were found while the simple antiferromagnetic arrangement remained the same. These observations are consistent with the Pr-O distance increasing with increasing Pr doping. No changes in the structure or magnetic behavior were found for the CuO 2 layers.