MOSSBAUER STUDIES AND MAGNETIC-PROPERTIES OF LN(2)SRCU(2)O(6) COMPOUNDS

Mossbauer and magnetic susceptibility measurements were used to study the magnetic properties of Ln(1.9)Sr(1.1)Cu(2)O(6) (Ln = Pr,Nd) and La 2SrCu2O6 materials. These compounds were prepared by solid-state react ion and crystallize in a tetragonal structure, space group I4/mmm with two formula units per unit cell. There is only one crystallographic s ite for Cu atoms, which form a double layer of CuO5 pyramids. These co mpounds are not superconducting, but we show, using Mossbauer spectros copy (MS) on iron doped samples and susceptibility measurements, that the Cu planes order antiferromagnetically. The hyperfine fields on iro n nuclei at 4.2 K extend from 472 kOe for La2SrCu2O6 to 501 kOe for Nd 1.9Sr1.1Cu2O6. The ordering temperatures TN are: similar to 20, 190, a nd 250 K for Ln = La, Pr and Nd, respectively.