Pulse laser irradiation of Ni, Co, and Co-Ni (or Ni-Co) targets in an oxygen background gas produced nanocondensates with rock salt-type structure. Analytical electron microscopic observations indicated that such nanocrystals are cubic in shape for NiO and cubo-octahedral for Co1-xO and Ni1-xCoxO. The nanocrystals coalesced predominantly with tl 001 or 11 1 11 facets to form nano chain aggregates or closer packed manner. The Co1-xO was more or less oxidized as Co3-delta O4 spinel with modulated distribution of defect clusters as indicated by diffuse side-band diffractions. (C) 2007 Elsevier B.V. All rights reserved.