I have deposited iron titanate thin films by electrodeposition at different molar concentration.
Q #1. In XRD pattern of as deposited I don't observe any intensity peak while after performing MF annealing at 300 degree Celcius, I observed intensity peaks. what's the basic reason behind this?
Q #2. At different molar concentration I observed different peaks except two peaks appeard on same plane. what will be main cause behind this?
Dear Adnan Kareem ,
I am not familiar with the chemistry of your compound;
but some general comments may help you:
Q #1: Annealing at elevated temperatures will cause/help crystallization of your material; so at the first stage of electrodeposition your film will be amorphous (no sharp peaks) and after the annealing turns into crystalline one (diffraction peaks appear);
you may share the XRD patter.
Q #2: Thin films tend to be textured; that means that in parts of your sample (thin film here) the crystallites of your material show preferred orientation; i.e. there is no homogenous angular/orientation distribution of your crystallites. In order to overcome the preferred orientation artifacts one makes use powder XRD, which in your case is not possible. But the application of a spinning sample stage could reduce these artifacts for you films.
With repect to the different molar concentrations, you may have different phases of your material and thus different peak positions...
Also here; you may share the XRD pattern...
Best regards
G.M.
Thank you Gerhard Martens for this useful answer.
I am going to add the XRD pattern
Compound is Fe2TiO4.
a. 0.01M
b. 0.02M
c. 0.03M
d. 0.04M
e. 0.05M
And can you elaborate about preferred orientation in these annealed XRD graphs?
Dear Adnan Kareem ,
thanks for sharing the XRD pattern...
They show what I have expected:
a) at the first stage all of them show broad peaks, which are related to amorphous structure
b) after annealing the XRD pattern partly exhibit 'crystalline' peaks. There are different distributions of peak heights, but no peak shifts. Here it is obvious that you suffer from preferred orientation of the crystallites in your films. To my opinion there is no significant hint on different crystalline phases.
Best regards
G.M.
Dear Gerhard Martens
I got it.
Thank you so much for your precious time.
if the crystallite size is increasing by molar concentration, is that possble the lattice paramater decrease by molarity increasing? if yes then what the reason behind this
Dear Adnan Kareem ,
to my opinion,
in your case there are some aspects with respect to the crystallization and crystallite size:
a) annealing temperature will cause crystallization;
b) annealing time and temperature will govern the crystallization process until no amorphous material is left; so time and temperature will responsible for the amount of all peak integrals;
c) primary molarity gives you the primary amount of material (here Fe2TiO4); thus the sum of peak integrals will be proportional to the molarity (but only in the case of sufficient high annealing temperature and sufficient time for complete crystallizaton of all the Fe2TiO4); (but only when no preferred orientation is present)
d) all the crystallized material will be the sum of all crystallites.
e) crystallite size affects the peak width (see 'Scherrer equation' and similar stuff); please check the peak widths in your case; pay attention: the peak heights will increase for smaller peak widths, but the peak heights also depend on the molarity and ... preferred orientation! ...
f) crystallite size will not affect the lattice parameters and thus not the peak positions
Best regards
G.M.
In my case the crystallite size increase while the lattice paramter decrease? how can I justify this in defence?
Dear Adnan Kareem ,
a) 'crystallite size increase' with increasing molarity?
There is no contradiction: the more material (here Fe2TiO4) is available the larger the crystallites can be...
b) decrease of lattice parameter means decrease of d-spacing; do you see really a peak shift to the higher 2thetas? (for increasing molarity)
How you can be confident, that this peak shift is not due to experimental issue, such for example misalignment in sample height position/sample surface positions. Larger film thicknesses will do that, unless a sample height correction is individually performed for each sample.
Best regards
G.M.
Dear Gerhard Martens
yes crystallite size increasing by increasing molarity.
not observe peak shift as much. as I have already attached the xrd graph.
It's mean is any experimental error occur?
Dear Adnan Kareem ,
you may have a look at a short text, which I have just uploaded.
It describes how the XRD peaks shift, when there is a height misalignment of the sample surface with respect to the nominal center of the goniometer circle. They are small for small misalignments and show a slight decrease with increasing theta (2theta).
If your films have got different thicknesses and you did not 'adjust' the film surface position with respect to the center of the goinometer circle you will have these peak shifts. You may roughly estimate your peak shifts when inserting your film thicknesses as the height misalignments h according to the formulae given in:
Presentation XRD and XRR angular shifts due to sample height variations
Best regards
G.M.
Okay Perfect.
Thank you so much for your useful answer and your time @Gerhard Martens
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