Evidence for Pr3+ in EuBa1.3Pr0.7Cu3O7-δ by 141Pr Mössbauer spectroscopy

Abstract The polycrystalline compound EuBa 1.3 Pr 0.7 Cu 3 O 7− δ has been prepared and investigated by the means of 141 Pr Mossbauer spectroscopy. The observed 141 Pr Mossbauer isomer shift, δ (at T =4.2 K)=0.10 (15) mm/s relative to PrF 3 , reflect a valence state of 3+ for Pr located at the Ba site in EuBa 1.3 Pr 0.7 Cu 3 O 7− δ . Magnetic order of the Pr sublattice was not observed at T =4.2 K in contrast with the compound Eu 0.3 Pr 0.7 Ba 2 Cu 3 O 7− δ where magnetic order of the Pr sublattice appears at T =12 K. Our results explain why Pr behaves very similar to other 3+ cations (La, Nd) when substituted for Ba in this system, and suggests that suppression of superconductivity by Pr substituted at the rare earth site is a consequence of the hole filling effect.