  Polarized neutron reflectometry (PNR) have developed theoretically and
experimentally in the past decades. In order to resolve the phase problem in
neutron reflectometry, several simulation methods have been proposed such as
reference layer and the variation of surroundings. By considering some factors
such as smoothness or roughness in simulations, it is tried to gain more
compatible results with experiment. In this paper, by using four different
functions "Linear, Airy, Eckart and Error function", we investigate the effects
of the smoothness of the interfacial potential on reflectivity, polarization of
reflected neutrons and determination of the SLD of the sample, using reference
layer method with polarized neutrons. We have also proposed a solution in order
to gain better results with less noise in output reflectivity data, at the
presence of smoothness.
