We present spectral variations of the binary X-ray pulsar LMC X-4 using the RXTE/PCA observations at different phases of its 30.5 day long super-orbital period .
Only out of eclipse data were used for this study .
During the high state of the super-orbital period of LMC X-4 , the spectrum is well described by a high energy cut-off power-law with a photon index in the range of 0.7 - 1.0 and an iron emission line .
In the low state , the spectrum is found to be flatter with power-law photon index in the range 0.5 - 0.7 .
A direct correlation is detected between the continuum flux in 7 - 25 keV energy band and the iron emission line flux .
The equivalent width of the iron emission line is found to be highly variable during low intensity state , whereas it remains almost constant during the high intensity state of the super-orbital period .
It is observed that the spectral variations in LMC X-4 are similar to those of Her X-1 ( using RXTE/PCA data ) .
These results suggest that the geometry of the region where the iron line is produced and its visibility with respect to the phase of the super-orbital period is similar in LMC X-4 and Her X-1 .
A remarkable difference between these two systems is a highly variable absorption column density with phase of the super-orbital period that is observed in Her X-1 but not in LMC X-4 .