A2BBO6 double perovskites are an important family of materials, with spintronic properties found in some examples e.g. Sr2FeMoO6. Although A2+ sites are usually occupied by non-magnetic cations such as Ca, Sr, Ba, recent work has shown that Mn2+ can be introduced using high pressures to create All Transition Metal double perovskites where all cation sites are occupied by magnetic transition metal ions. We have recently prepared Mn2NiReO6 which has a monoclinically distorted P21/n double perovskite structure and a ferro/ferri- magnetic transition at 100 K. One day of beamtime at WISH is requested to determine the accurate crystal structure, where the neutron scattering length contrast of Mn, Ni and Re (-3.73, 10.3 and 9.2 fm, respectively) will detect any A/B site disorder and O-positions will give accurate octahedral tilt angles, and the magnetic order of the 3 spin sublattices.
