Saeed S. Jahromi - Department of Physics, K.N. Toosi University of Technology, P.O. Box ۱۵۸۷۵-۴۴۱۶, Tehran, Iran
Seyed Farhad Masoudi
Majid Hojjatpanah - Department of Material Science, Shiraz University, Shiraz, Iran

As an atomic scale probe, Polarized Neutron Reflectometry (PNR) has had a vast application to the study of surface structure and properties of magnetic thin films. Reflection of polarized neutrons from multilayer thin films would provide us with useful information about thickness, type and properties of neutron wave function inside the sample. Orientation and strength of intrinsic magnetic fields inside the ferromagnetic films would affect the interacting potential of neutrons with the sample (optical potential) and as a result, would rotate the spin of reflected neutrons (Spin-Flip Reflectivity) and change the retrieved scattering length density (SLD) of the sample. In this paper, we have investigated the effects of different orientation of magnetic fields inside the ferromagnetic thin films on reflectivity and SLD of the sample. We have also studied the resonances of neutron wave function inside the ferromagnetic films. The results show that the changes in direction of magnetic field can make the resonances to appear below the critical values of neutron wave number on reflectivity curve, and change the absorptive characteristic of ferromagnetic thin films

Polarized Neutron Reflectometry; SLD; Multilayer system; Neutron resonance; Spin-Flip Reflectivity