Crystal and magnetic structures of the NdMnMnReO6 double double perovskite

Perovskites, ABO3, can be modified to induce cation orderings at A and B sites in double double perovskites AA’BB’O6 (DDPv). We have recently synthesised the first member of a new DDPv series, NdMnMnReO6. This is notable for having all four A/A’/B/B’ cations being magnetic – the first time that this has been achieved in DDPv’s. Magnetic susceptibility measurements reveal two magnetic transitions at TC1 = 233 K and TC2 = 69 K. The M-H hysteresis loop at 100 K shows a moment of ~4 BM/f.u. consistent with a simple up-Mn/down-Re spin ferrimagnetic order but M-H at 2 K has a much smaller ordered moment ~0.5 BM/f.u. revealing a more complex order. Neutron diffraction is needed to investigate the crystal structure (esp. any Nd/Mn or Mn/Re antisite disorders and accurate metal-oxygen distances for BVS calculations) and T-evolution of magnetic order. Hence 2 days on WISH are requested.