Basal plane ferromagnetism in the rhombohedral manganite La0.85Ag0.15MnO3+?

The structural and magnetic properties of silver-doped lanthanum manganite, La0.85Ag0.15MnO3+delta, delta = 0.10(2), have been studied using magnetometry and high-resolution neutron powder diffraction. The structural space group is found to be predominantly R (3) over barc, with a minor (5%) fraction of Pnma phase. This phase fraction does not change in the measured temperature range of 4 K to 300 K. Our high-resolution diffraction data allow a detailed analysis of the spin orientation. Using representational analysis, we find the ferromagnetic state below T-c = 246 K has spins oriented perpendicular to the rhombohedral c-axis and is purely ferromagnetic i.e. no canting between sublattices is observed. Implications for the magnetocaloric effect are discussed.