If the experimental and refined peaks are not matching check the space group or initial lattice parameters.

If you have issues with peak intensities I can see a few possible (generic) explanations:

- Bad statistics due to grain-ness

Possible (generic) solutions-> use more sample, use finer powder (if it's a powder, of course), spin the sample during the data collection, etc.

- Preferred orientation

Model the preferred orientation in your Rietveld analysis.

- Wrong crystal structure

Check especially atom species and/or occupancies, if it appears to be the case (es. if you have hints from EDS measurements in your phases, or other knowledge about the characteristics of your phases).

Good luck

Dear Rudra:

As indicated by Marco Voltolini, one possibility is the prefered orientation, the other is the difference of element in your alloy and those in the input crystructure. Please click prefered orientation and FWHM during refining. You may also change the input structure.

The first hyphothesis is a preferred orientation effect, but also the occupancies have an high importance, particularly in your case in which a mixed occupation on sites is present.

At low angles, the X-ray beam is spread over a larger surface of the specimen than it is at high angles if it is flat plate sample holder used. In such cases use of an automatic divergence slit can be made. Second might be preferred orietntation which can be minimised by rotating the sample during data colloection. Till if it is there, check the structural inputs in model.....