LiMn2O4 low-temperature phase: synchrotron and neutron diffraction study

The structural evolution of LiMn2O4 spinel was followed from 320 K down to 10 K. The structural transformation, recently studied down to 230 K [Rodrig uez-Carvajal, Rousse, Masquelier & Hervieu (1998). Phys. Rev. Lett. 81, 466 0-4663], takes place near room temperature with a significant hysteresis: t he high-temperature cubic phase transforms to a superstructure orthorhombic cell. The present study indicates that the nuclear structure is stable dow n to 10 K, while neutron diffraction patterns below 80 K show the rise of a magnetic ordering in the spinel phase. From Mn-O bond-length analysis of t he MnO6 octahedra, a temperature-independent charge ordering in the structu re can be deduced.