Magnetic properties of ordered perovskites Ba(2)LnIrO(6) (Ln = Sm, Eu, Gd,and Yb)

Magnetic properties of ordered perovskites Ba(2)LnIrO(6) (Ln = Sm, Eu, Gd, and Yb) are reported. Their magnetic susceptibilities were measured from 2 to 350 K. The Eu-151 Mossbauer spectrum of Ba2EuIrO6 and the electronic par amagnetic resonance (EPR) spectrum of Ba2GdIrO6 were measured at room tempe rature. Ba2EuIrO6 and Ba2SmIrO6 show Van Vleck paramagnetism. A. spin-orbit coupling constant of the Eu3+ ion is determined to be 364 cm(-1). The Moss bauer spectrum of Ba2EuIrO6 shows that the Eu ion is in the trivalent state , and the symmetry of the Eu site is slightly distorted from an octahedral symmetry because of the existence of a quadrupole interaction. The magnetic susceptibilities of Ba2GdIrO6 and Ba2YbIrO6 follow the Curie law and the c rystal field splitting of the Yb3+ ion is calculated. The g value of the Gd 3+ ion in Ba2GdIrO6 is determined to be 1.99 and Gd3+ is very slightly affe cted by the crystal field from the EPR measurement. (C) 1999 Academic Press .