  The title compound Ba3RuTi2O9 crystallizes with a hexagonal unit cell. It
contains layers of edge shared triangular network of Ru4+ (S=1) ions. Magnetic
susceptibility chi(T) and heat capacity data show no long range magnetic
ordering down to 1.8K. A Curie-Weiss (CW) fitting of chi(T) yields a large
antiferromagnetic CW temperature theta_CW=-166K. However, in low field, a
splitting of zero field cooled (ZFC) and field cooled (FC) chi(T) is observed
below ~30K. Our measurements suggest that Ba3RuTi2O9 is a highly frustrated
system but only a small fraction of the spins in this system undergo a
transition to a frozen magnetic state below ~30K.
