The hexagonal perovskites make up a large and technologically useful class of oxide materials, with applications as diverse as dielectric resonators for mobile phones and fuel cell membranes. However, the structure-property relationship in these materials is poorly understood. We have recently investigated the interplay between local electronic/magnetic and lattice degrees of freedom in these systems. Ba3NdRu2O9 has a particularly rich phase diagram undergoing a structural distortion at 120 K and at least two distinct magnetic ordering transitions at lower temperatures (~20 K) resulting in substantial magnetostriction. Hysteresis loops show that at 2 K and the reversal of magnetization proceeds 1/3-magnetization steps. A 5 g polycrystalline sample of Ba3NdRu2O9 is available. 2 days with a cryomagnet on WISH are requested to study the magnetic structure(s) in the field range 0-5 T.