Magnetic hyperfine fields at In-111 probes in submonolayer Cu islands on Co(100) surfaces

Cu islands in the submonolayer coverage regime deposited on Co(1 0 0) have been studied utilizing the PAC spectroscopy. The In-111 PAC probes are inco rporated into the topmost monolayer, which is corroborated by the presence of a rather unique electric field gradient. In addition, weak magnetic hype rfine fields B-hf between 1.9(2) and 0.37(4) T have been observed depending on the Cu coverage. This is attributed to next neighbours of the PAC probe s consisting of mixed Co/Cu configurations. A linear decrease of Bhf as a f unction of the number of Cu atoms replacing Co is found.