Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms vol:190 pages:840-845
A variety of nuclear techniques rely on the incorporation of radioactive atoms to investigate the microscopic structural, electronic and magnetic properties of a material. In the past, ion implantation has been utilized to introduce these radioactive probes, resulting in a depth distribution of typically several hundreds of A, and damaging the sample. Both implantation-related deficiencies are incompatible with the ever shrinking sizes relevant in nanostructures. This problem can be circumvented by using ultra-low energy ion beams - of the order of 5 eV, i.e. below the displacement energy of the substrate atoms. Consequently, the radioactive probes are "deposited" on top of the sample. without generating damage to the substrate. Since the implantation chamber is in vacuo connected with the molecular beam epitaxy deposition chamber, the probe layer can be introduced at any stage during the sample growth (from surface to interface)-with monolayer depth resolution. As an example, we discuss the ultra-low energy ion deposition of In-111 in Cr. followed by analysis with perturbed angular correlation spectroscopy. The aim of the study is to explore the magnetic ordering of Cr thin films. (C) 2002 Elsevier Science B.V. All rights reserved.