Something for consideration: for the Br sample there seems to be a gradual rise in intensity of the baseline from 20 2-th up to 30 2-th and then a gradual reduction again to ~37 2-th. This may indicate that this sample has a greater amorphous component than the Cl sample. The reduction in intensity could be linked to a lower degree of crystallinity.
It may be worthwhile to mention that it is more appropriate to compare the integrated intensities, because the peak height also depends on the microstructure broadening.
So if take the CdTiO3 as reference in both samples the individual structure factors F^2 for each hkls are constants, the LP factor and incident intensity (if you measured both samples with the same counting times) are constants. So what is left is the sample. On the sample side there a some factors to consider: Chemical composition -> the mass attenuation coefficient of you sample will be inversely proportional to the irradiated volume; Higher MAC lower irradiated volume -> less intensity; Phase composition -> evidently lower CdTiO3 will mean lower fraction of CdTiO3 in the irradiated sample volume -> lower intensity. If you have inappropriate big particle sizes you may encounter micro absorption (quite difficult topic) the easy way would be to regrind your sample in order to exclude this factor.
I suggest you should try a Rietveld quantification to evaluate the phase fractions and do some chemical analysis like XRF to get more informations on your sample...
Something for consideration: for the Br sample there seems to be a gradual rise in intensity of the baseline from 20 2-th up to 30 2-th and then a gradual reduction again to ~37 2-th. This may indicate that this sample has a greater amorphous component than the Cl sample. The reduction in intensity could be linked to a lower degree of crystallinity.
How did you introduce the powder into the sample holder? Pressed for uniform packing and constancy of diffracting volume?
What is the typical grain/particle size in the sample? Any micrographs?
How sensitive is your diffractogram to the location of the sampling volume on the sample surface? What is the sampling size (beam size, slit size etc.)?
Suggestions:
Normalize the relative intensity w.r.t. the total integrated intensity for each profile and then compare.
Post the ASCII or Excel files with the original data.
Include the effect of beam conditioning (instrumental profile), strain/stress, defects, preferred orientation, amorphous constituent etc. in your analyses.
Once you normalize your data, comparing different data sets will be facilitated: