K-XANES STUDIES OF 3D-TRANSITION METAL DOPANTS IN YBA2(CU1-XMX)3O7-DELTA - X LESS-THAN-OR-EQUAL-TO 0.10 AND M = MN TO NI AND ZN

In continuation of our earlier report on the EXAFS studies, we present here the results of K XANES measurements on the 3d dopants, Mn to Ni and Zn, in the 1-2-3 lattice. It is found, perhaps for the first time, that the Mn dopant in a 1-2-3 lattice is in a divalent state. It is inferred from the K XANES features that Mn occupies the Cu(1) chain site in the 1-2-3 lattice. The results of our consolidated K XANES measurements on the valence states of Fe, Co, Ni and Zn dopants are consistent with the earlier reports on these heavy 3d ions in 1-2-3 compounds.