STRUCTURAL AND ELECTRONIC-PROPERTIES OF THE DILUTE MAGNET SR3XLA2-3XZN1-XRUXO4 (1 ESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-2/3)/

The solid solution Sr3xLa2-3xZn1-xRuxO4 (1/3 less-than-or-equal-to x l ess-than-or-equal-to 2/3) has the tetragonal K2NiF4 structure with a d isordered arrangement of Zn2+ and Ru5+ over the octahedral sites. The sample with x = 1/3 is found to be paramagnetic over the temperature r ange 6 < T < 296 K. As the ruthenium concentration increases, short-ra nge antiferromagnetic interactions between Ru5+ ions become more impor tant; the magnetic susceptibility shows a maximum at low temperatures when x is larger than the percolation threshold for a nearest-neighbor square lattice (0.59). However, the magnetic irreversibility observed for the samples with x =1/2 and 2/3 indicates that next-nearest-neigh bor interactions also play an important role in determining the magnet ic properties of these compounds. (C) 1994 Academic Press, Inc.