The smaller is the size of your particles, the broader will be the peaks (roughly according to the Scherrer equation). The position that you mention looks reasonable for the {111} peak of Co.

The size of your nanoparticles can be so small that they become virtually undetectable with lab xrd. Since you barely see the 111 reflection, you probably have quite small NPs. In any case check your xrd setup and try to maximize your signal (remove pinholes, narrow slits, Ni filter and count longer). 

If you can, do GIXD, to avoid any contribution from your substrate and just see your NP film.

what is FWHM of the peak?

1.1520 (two theta)

Please refer our paper published in AMR

As adition of answer from Alexander B. Missyue, which is very possible, it is also reasonable that it is not obtain crystallized Co nano particle-metal glass nano particel. In that case is to fast under cooling by the process of crystallization. It shell be obtain different properties after tempering of you obtained nano Co.

I can suggest you to go for SAED instead of XRD.....

Still, if you would like to perform XRD for the nano particles, you can reduce the slit width (normally, they use 10 mm - 1mm, but you can go for 0.1 or 0.01 mm slits).

In my opinion it is because of material having large distribution of particle sizes.

Dear Chandraprabha,

This is I attach JCPDS file for Co.

Hopefully, it can help.

Cheers,

Indra Pardede

Dear brother, actually cobalt ferrite synthesis by chemical methods with minim calcined temperature (  350 C), shows 8 fundamental peaks in the 2 theta range (20-80), in your cause I think there is problem in the way of preparation and that peak at value 44.18  is mention for Co peak .    

Have you confirmed the nano size of the particle under SEM or TEM? How broad is the size distribution? 

My suggestion is, if there is no sharp peaks and it appears broad it is a nano-sized particle. You can confirm with SEM observation

Dear brother, you can using both equipment to confirmed the nano-size of your samples, but TEM can measurement size of your particles with very low  percentage of line.

thank u all

Over the last years, there have been quite a few threads here on RG dealing in much detail with what TEM and XRD "have on offer", respectively. I would warmly recommend you to seek these discussions in order to make sure you understand what it takes to (i) understand each technique and (ii) how their results (many times don't) compare qualitatively and quantitatively.  Quite a few of these threads have Matteo Leoni as a very competent contributor. This might offer you a way to find the relevant threads.

First you check the thickness of the film and on which substrate you have deposited.Thereafter I can surely say that why there is no sharp peak obtained in the xrd patterns also the intensity of the peak is depends on the method of preparation. Please check this point.

Hi, l thought that the  annealing temperature isn't  enough to formation cobalt phase.

Fall in line with others, noisey and broadened peaks indicate nano nature. Sintering below 6000 C produce nano.Increase of sintering temperature may lead to sharp peaks but become bulk. I vaguly remember, XRD particle size, is better than any thing else published in ACS(Journal name I am not remembering). But if facilities are available, better go for TEM also. 

If you are sure about the synthesis and formation of nanoparticles, follow the suggestions by Sakthivel Gandhi. If still you don't get a peak, check with TEM.

May be this article can be useful

As particle size decreases into the nano range, you get peak broadening. 

As particle size decreases. chances of having similar crystal structure over a large ares becomes improbable. Hence it is difficult to get high peak intensities for nano material unless you have very crystalline powders.

Hi Chandra, in addition to those previous answers, In my opinion, it is better you describe first your preparation procedure. For instance, whcih cobalt (or cobalt oxides) structure or compound you wish to be prepared and what temperature calcination did you use....Therefore, by comparing the representative peaks of your sample and the reference ( three or four peaks : with vs, s, and m intensities). In your case you have just obtained one peak at 44.18 ( in fact that peak position, it is not a very strong and representative main peak of all cobalt oxides compounds). Regarding the nano, it has been explained.

your preparation technique, heating temperature are important before making a strong conclusion. Cobalt metal and oxide will definitely show 2 theta peaks if the phase is formed. To say a solid inorganic compound is formed, XRD is considered to be the most authentic. 

If cobalt oxide formed with high carbon content similar results are usually observed usually by sol-gel method.