Single-crystal hollandite-type manganese oxides Ba1+delta Mn8O16 nanoribbons (width of 30-500 nm and up to several hundred micrometers long) are synthesized by a simple molten-salt method. At 43 K a rapid increase of magnetization is observed; the zero field-cooled (ZFC) and field-cooled (FC) magnetization curves diverge below this temperature with a sharp cusp around 26 K in the ZFC curve revealing spin-glass-like behavior in the Ba1+delta Mn8O16 nanoribbons. Measurements of ac-susceptibility indicate the coexistence of a weak ferromagnetic phase with a spin-glass component in the nanoribbons, which is distinct from the canted antiferromagnetic state found in the counterpart bulk sample. (C) 2010 Elsevier B.V. All rights reserved.