What is exactly the material that you are working? XRD is, in my opinion, the best method for crystalline materials. It is just about know how to work with it.

About impurities, with more information about the material that you are working in, maybe we could find an explanation. It is important, as well, to know how did you prepare the sample. 

In XRD, sample preparation is one of the MOST important things to reguard, specially for high prefferencial orientation materials.

happy to tell u is that u entered into research field.

dont change the XRD machine change the material or find out the what impurities u r getting try to minimize by repeated calcination in solid state or change the synthesizing parametrs r solvents using in wet chemical methods. if u tell ur material and the path u choosen phase pure compounds then our research gate scholars will help u.

william, what is the need for going optional characterization, i agree with grande do sul, my opinion is try to optimize the condition ( specify your compound name and preparation method), in particular if your are preparing bismuth ferrite, try to anneal at 600 oC for wet chemical synthesis, even in this condition you may get impurity phases but relatively low, if  it is a solid state reaction try to quench it from the furnace heating it to 800-830oC (30 min - 1 hr).

Mr.Venkat and Paul Sir, My material is Bismuth ferrite doping with Bismuth chromate, by spin coating  I am using solgel route for my synthesis but i'm getting impurity even after calcination, Whether i have to change calcination atmosphere??

Can you do your sample preparation in an inert atmosphere, such as a glove box or similar ? 

Also Neutron diffraction and XRF techniques are also good for characterization, although for neutron work you need bulk samples due to penetration depth.

Your impurity would seem to be occurring during your sample creation phase, thus an inert atmospher may help.

There are many other techniques such as neutron or synchrotron scattering. However, they are normally difficult to access and requires more knowledge to handle. However, all of them have their advantage and limitations, not the more expensive the better. XRD is always the easiest one and cheapest one. There are many ways to improve your XRD measurement, such as increasing the resolution and intensity.  How you prepare your sample and how you setup may also affect your results. 

Impurities can be introduced in many ways. They can come from your source power, your contaminated furnace, your un-reacted or over-reacted chemicals, etc.. Maybe improve your XRD measurement technique may help you to find out what impurities they are, then you can start to find a way to deal with them,  

hello William, with my lab experience on BFO synthesis, i try to share it with you. see, it is quite difficult to prepare a single phase  BFO due to its kinetics. we are able to get relatively pure BFO (not exacly pure) with simple nitrate decomposition just as given in the bolded article.

if you see in all the given article you find that at 500 - 600 oC is the optimized phase of BFO irrespective of the preparation.

i hope with my intuition, your are using possibly a glass substrate, which would prevent you of reaching this temperature. if it so, try the method adopted in the bold italic  link.

also, your route defining sol-gel is unclear in the usage of chelalting agent, you can use polydentate ligand specifically tartaric acid or ethylene glycol : citrate ratio .

set Ph ~4 for the solution, avoid  excess  water usage, this will cause Bi complex compound to Bi oxynitrate, lead to impurity phase.

http://www.sciencedirect.com/scienc be/article/pii/S0025540813002535

http://www.sciencedirect.com/science/article/pii/S0167577X14004637

http://www.sciencedirect.com/science/article/pii/S0167577X08004941

http://www.tandfonline.com/doi/full/10.1080/00102202.2013.859682#abstract

http://arxiv.org/ftp/arxiv/papers/1502/1502.05921.pdf

http://link.springer.com/article/10.1007%2Fs10948-014-2674-1.