Surface x-ray diffraction has been used to investigate the growth and struc
ture of thin cobalt deposits on a Pt(110) substrate. The substrate exhibits
the missing-row reconstruction, which has been checked and refined with cr
ystallographic measurements. Co grows in the Stranski-Krastanov mode: an in
itial two-dimensional growth followed by three-dimensional crystallites. In
the early growth stages, cobalt fills the missing-row sites and mixes with
Pt. Subsequent growth results in the formation of long triangular prisms w
ith the largest side in contact with the substrate. These crystallites have
the fee structure and their lateral faces are 111 planes. [S0163-1829(99)0
9603-4].