Synthesis, structural chemistry and magnetic properties of La1+xA1-xInMnO6-δ:: A = Ba, Sr; x = 0, 0.2

A series of novel double perovskites La(1+x)A(1-x)InMnO(6-delta) (A = Sr, Ba) has been prepared and the room temperature crystal structures have been refined using X-ray and neutron powder diffraction. In all cases the B-site is occupied by a disordered arrangement of In3+ and Mn3+/4+ cations. However, whereas La1+xBa1-xInMnO6-delta exhibits two octahedral tilts and exists in a body-centred cell, space group Imma, La1+xSr1-xInMnO6-delta adopts the three-tilt GdFeO3 structure and has a primitive orthorhombic structure, space group Pnma. Magnetic susceptibility data show that all the compositions synthesised exhibit a spin glass freezing transition at similar to8 K. A negative magnetoresistance Delta rho/rho (0) = 10.5% was measured at 164 K in a field of 14 T.