Magnetic order and superconductivity in RBa/sub 2/Cu/sub 3/O/sub z/

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.38.6677· OSTI ID:6933767

Nowik, I; Kowitt, M; Felner, I; Bauminger, E R

Moessbauer studies of /sup 57/Fe in RBa/sub 2-//sub y/K/sub y/(Cu/sub 1-//sub x/Fe/sub x/)/sub 3/O/sub z/, with R = Y and Pr, y = 0 and 0.5, x = 0.01, 0.05, and 0.1, z between 5.9 and 7.1, have been performed. A minority of the iron ions enter the Cu(2) site and reveal its magnetic order. For R = Y, y = 0, and x = 0.1, T/sub N/ equals 280 and 415 K for z = 6.5 and 6.1, respectively. The magnetic moments lie in the basal plane. In tetragonal, oxygen-rich PrBa/sub 2/(Cu/sub 0.9/Fe/sub 0.1/)/sub 3/O/sub 6.9/, T/sub N/ = 325 K; in superconducting YBa/sub 2/(Cu/sub 0.9/Fe/sub 0.1/)/sub 3/O/sub 7.1/ there is no magnetic order. In nonsuperconducting YBa/sub 1.5/K/sub 0.5/(Cu/sub 0.95/Fe/sub 0.05/)/sub 3/O/sub 6.1/ two distinctly inequivalent magnetic iron sites are observed, corresponding to iron in the Cu(2) site with different Ba-K neighbors. Moments of iron ions that have three Ba and one K as first nearest neighbors have a different temperature dependence and T/sub N/ (T/sub N/ = 450 K) from those with four Ba neighbors, where T/sub N/ = 415 K, showing that the antiferromagnetic exchange in the Cu(2) planes is strongly affected by the replacement of Ba/sup 2+/ by K/sup +/, probably by repelling oxygen from the Cu(2) plane. In superconducting YBa/sub 1.5/K/sub 0.5/(Cu/sub 0.95/Fe/sub 0.05/)/sub 3/O/sub 6.5/ the iron site with T/sub N/ = 450 K remains magnetic. The implications of these findings on the valencies of the Cu ions are discussed.

• Research Organization: Racah Institute of Physics, The Hebrew University, 91chemically bond904 Jerusalem, Israel
• OSTI ID: 6933767
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 38:10; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EVEN-ODD NUCLEI
HIGH TEMPERATURE
INTERMEDIATE MASS NUCLEI
IRON 57
IRON COMPOUNDS
IRON ISOTOPES
IRON OXIDES
ISOTOPES
LOW TEMPERATURE
MAGNETIC MOMENTS
MEDIUM TEMPERATURE
MOESSBAUER EFFECT
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RARE EARTH COMPOUNDS
STABLE ISOTOPES
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
VALENCE
VERY LOW TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES