Magnetic properties of rare earth nickelates for the Ln{sub 2} Ba Ni O{sub 5} family Gundakaram, R [Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore (India)]; Vasanthacharya, Y [Indian Inst. of Science, Bangalore (India). Solid State and Structural Chemistry Unit]; Ganguli, A K; Rao, C N.R. [Indian Inst. of Science, Bangalore (India)] 36 MATERIALS SCIENCE; NICKELATES; CRYSTAL STRUCTURE; MAGNETIC SUSCEPTIBILITY; ANTIFERROMAGNETISM; BARIUM COMPOUNDS; COPPER COMPOUNDS; CURIE POINT; DYSPROSIUM COMPOUNDS; MAGNETIC MOMENTS; NEEL TEMPERATURE; NEODYMIUM COMPOUNDS; PARAMAGNETISM; X-RAY DIFFRACTION Rare-earth nickelates Ln{sub 2} Ba Ni{sub 1-x} Cu{sub x} O{sub 5}, Ln = Nd and Dy, and Dy{sub 2-x} Y{sub x} Ba Ni O{sub 5} have been synthesized in order to investigate the effect of substitution of Ni by Cu and Dy by nonmagnetic Y on the magnetic properties of the nickelates. In Ln{sub 2} Ba Ni{sub 1-x} Cu{sub x} O{sub 5}, the nickelate structure (x=0.0) changes to the cuprate structure (x=1.0) at a specific composition (x=0.3). The Neel temperature of Nd{sub 2} Ba Ni{sub 1-x} Cu{sub x} O{sub 5} decreases continuously with increase in x up to x=0.3 (T{sub N} = 18 K); when x > 0.3, the materials are paramagnetic down to 20 K. The effective magnetic moment ({mu} eff) in Nd{sub 2} Ba Ni{sub 1-x} Cu{sub x} O{sub 5} essentially corresponds to the contribution of the Nd ions. In Dy{sub 2-x} Y{sub x} Ba Ni O{sub 5}, the Neel temperature decreases from 40 K when x=0.0 to 24 K when x=1.5. The compositions with 1.5{<=}x<2 (including the x=1.95 composition) are paramagnetic down to 20 K, unlike Y{sub 2} Ba Ni O{sub 5} (x=2.0) which exhibits a T{sub N} of 370 K. Even the smallest concentration of paramagnetic Dy seems to destroy the antiferromagnetic Ni-O-Ni chains in Y{sub 2} Ba Ni O{sub 5}. (authors). 10 refs., 7 figs., 1 tab. France 1996-10-01 English Journal Article Journal Name: European Journal of Solid State and Inorganic Chemistry; Journal Volume: 33; Journal Issue: 1; Other Information: PBD: 1996 Medium: X; Size: pp. 41-52 https://doi.org/ [] 1 33 Journal ID: EJSCE5; TRN: FR9602201067735 FRN; SCA: 360204; 360202; PA: AIX-27:067735; EDB-96:143881; SN: 96001670572 2010-12-29 373083