  We have performed pulse phase resolved spectroscopy of the Cyclotron
Resonance Scattering Features (CRSF) of some bright accretion powered X-ray
pulsars like 1A 1118-61, Vela X-1, A0535+26, XTE J1946+274, 4U 1907+09, 4U
1626-67 and GX 301-2 using Suzaku observations with long exposures. We have
performed the study using different spectral models for the continuum and have
obtained similar patterns of variations of the CRSF in all the cases, thus
demonstrating the robustness of our results. Pulse phase dependence of the CRSF
in XTE J1946+274 has been obtained for the first time, and phase resolved
variations of the CRSF in 4U 1907+09 has been compared at factor of ~ 2
difference in luminosity. We have also studied the pulse profiles of these
objects near the CRSF energy, and have noticed an increased pulse fraction
and/or a change in the pulse shape near the CRSF energy for some sources. The
implications of the results are discussed.
