Characterisation of ferromagnetic magnetic storage media surfaces by complementary particle induced X-ray analysis and time of flight-energy dispersive elastic recoil detection analysis

Thin (10 nm-1 mu m) films of ferromagnetic material constitute an important class of materials that are difficult to analyse by conventional ion beam analytical (IBA) techniques because they are based on the ferromagnetic ele ments (Co, Fe, Mn, Ni, and Cr). The similar or overlapping isotope masses m akes it difficult to separate the elemental signals using time of flight an d energy dispersive elastic recoil detection (ToF-E ERD). In this explorato ry study we have investigated the use of Particle Induced X-ray Emission (P INE) measurements to refine the mass dispersive depth profile information f rom ToF-E ERD. The surfaces of two commercial magnetic media were investiga ted, One sample was a 3 1/2" double density diskette with a coating of ferr ite particles in an organic binder, The other sample was a complex C/Co/Cr/ Ni-P/Al multilayer structure taken from a standard hard disc. The Lund nucl ear microprobe with a 2.55 MeV proton beam was used for PIXE analysis. ToF- ERD measurements were carried out using a 55 MeV I-127(10+) ion beam incide nt at 67.5 degrees to the surface normal. The time of flight and kinetic en ergy of recoils ejected at 45 degrees to the ion beam direction was measure d in a detector telescope. The findings demonstrate that by detailed analys is of the PIXE spectra it is possible to remove the ambiguities in mass ass ignment of the ToF-ERD data associated with the ferromagnetic elements. (C) 1999 Elsevier Science B.V. All rights reserved.