In my limited knowledge, most of the baseline comes from amorphous parts of the sample. When you sintered in higher temperature, your sample obtained better cristaline---less amorphous parts in your sample and less baseline. The straight baseline may be due to another reason. 

Does this explanation make sense?   

My question is that at low sintering temp, the baseline was curvy. There were characteristi peaks, the sample was near to perfection. 

The XRD with higher sintering temp had a very much flat baseline, with the characteristic peaks. 

So why the change in baseline?

Dear Vishesh,

it is just as Yoshiki explained above: structure (broad flat peaks or 'curvy' sections) in the baseline are due to amorphous constiutuents of your sample. Higher sintering temperature will lead to crystallite growth and thus to a reduction of amorphous contribution in the sample and thus to a reduction of the base line down to a very flat and small one.

In addition I expect you have got higher diffraction peaks for the sample sintered at higher temperature due to increase in crystallinity. But be carefull in the comparison: the absolute peak heights may depend on sample adjustment.

But what's the thickness of your sample and what's your film substrate? These issues might arise from your substrate. I don't expect that the film thickness changes with sintering temperature.  

Thank you for your answer-Gerhard

Dear Vishesh Saxena

Have a nice day

I strongly concur with Dr. Yoshiki Fukada and Dr. Gerhard Martens. The sintering process is usually leads to increase the crystallinity of the sample and then to get more crystalline sample than before sintering. Increasing the crystallinity of the sample comes on the account of the non-crystalline part which may present in your sample, which is responsible on the the variation of the baseline of XRD pattern. Taking into account that this non-crystalline part is randomly distributed along the whole sample, thereby at low sintering temperatures, the baseline has not constant level and varied according the presence of the amorphous part.

Raising the sintering temperatures will cause redistribution for the amorphous part along the whole sample (almost by equality) and then leads to the increasing of the crystallinity of the sample. Therefore, the baseline has observed as it doesn't change.

Moreover, the sintering process leads to the compacting and forming the solid mass of material by heat or pressure without melting it to the point of liquefaction. The atoms in the materials diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece. This may lead to decreasing of the thickness of the sample.

Good luck

I have one more doubt. It is said that compounds having ABO3 type chemical formula have perovskite  structure. So why Gafeo3 is not perovskite according to the rule? 

Dear vishesh

I thank that it will be more suitable that if you make this question as a new one.

Good luck

• Avoid using Cu K Alpha in the incident beam?
• Film thickness?
• Substrate?

Thank you everyone for your answers!