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We present spectral variations of the binary X-ray pulsar LMC X-4 using theRXTE/PCA observations at different phases of its 30.5 day long super-orbitalperiod. Only out of eclipse data were used for this study. During the highstate of the super-orbital period of LMC X-4, the spectrum is well described bya high energy cut-off power-law with a photon index in the range of 0.7-1.0 andan iron emission line. In the low state, the spectrum is found to be flatterwith power-law photon index in the range 0.5-0.7. A direct correlation isdetected between the continuum flux in 7-25 keV energy band and the ironemission line flux. The equivalent width of the iron emission line is found tobe highly variable during low intensity state, whereas it remains almostconstant during the high intensity state of the super-orbital period. It isobserved that the spectral variations in LMC X-4 are similar to those of HerX-1 (using RXTE/PCA data). These results suggest that the geometry of theregion where the iron line is produced and its visibility with respect to thephase of the super-orbital period is similar in LMC X-4 and Her X-1. Aremarkable difference between these two systems is a highly variable absorptioncolumn density with phase of the super-orbital period that is observed in HerX-1 but not in LMC X-4.Comment: 7 pages, 5 figures, Accepted for publication in Astronomy and  Astrophysic

Spectral variations of the X-ray binary pulsar LMC X-4 during its long period intensity variation and a comparison with Her X-1