ESR spectra are recorded for the powdered samples[ say five] of BaTiO3[ fabricated by rate controlled synthesis] of known average sizes[ say 35,48,60,86 and 98 nm] at room temperature with ESR spectrometer operating at 9.4 GHz as follows:

We place turn by turn powdered samples of known particle size in the ESR cell along with the standard solid substance called DPPH[ SEE ATTCHMENT] placed in the same cell but in a separate tube. So both the BaTiO3 sample and DPPH experience same strength of magnetic field.

Depending upon the nature of the paramagnetic species[ Say Fe^3 ] present, the ESR spectrum of each sample[ of different sizes ]will give a number of peaks along with the peak of the DPPH[ generally distinguished from the sample peaks by it being a DOTTED peak].

We note the magnetic fields( in Gauss) at which the dotted DPPH peak[ say H(DPPH)] and the other peaks of the sample[H(BaTiO3)] appear.The value of “g” of the DPPH [ g(DPPH)] is taken as standard to be equal to 2.0023

By applying following formula, we calculate “g” values of all the peaks of BaTiO3 as:

g (BaTiO3)=g(DPPH).H(DPPH)/H(BaTiO3)

Put g(DPPH) = 2.0023[ The standard value] and calculate the “ g” values of the various peaks of the fiveBaTiO3 samples of various sizes.

Though the number of peaks and their “g” values will differ with the nature of paramagnetic species present in BaTiO3, yet some common features are observed in the ESR of all types of perov skites as:

(i)The line shape and intensity are strongly dependent on the particles size.

{ii}The decrease of intensity and broadening of line is observed with the decrease of particle size.

(iii)The characteristic feature of the line shape is its asymmetry which increases with the decrease of the size of NP.

(iv)The observed line may arise from a superposition of at least two independent lines.

(v) Now a days,the computer stimulation has made it possible to extract these two lines; the ratio of their integral intensity being dependent on the particle size.

Thanks for your information.

I am using X-band measurement only

But i need to clear one thing, alone few mg of BaTiO3 is enough with out any solvent.

BaTiO3 is not conductive material. 

Yes. Moreover, the sample can be reused because it is not mixed with DPPH which is filled in a  separate sealed tube  but is placed in the same cell where BaTiO3 is to be placed. 

Tomorrow, i will try that.

I am greateful to you.  

If you are only using a few mg of sample in a tube, make sure it is sitting in the centre of the cavity. You made need to do some repeat experiments with your single crystal DPPH standard lowering it 2mm at a time to establish the exact sweet spot of the cavity. Then locate your sample centred there. Regards

Frederick, Manohar and Philip have already given full detailed aswer to your question. Let me add some words from my past experience. In order to get quantitative and comparable results between samples (may be you need to compare the intensity of some spectra components between two samples or among more samples or to compare fulle spectra inensities: you might pay some attention in making exactly equal samples with the same amounts and in beig sure that these amounts go completely into the cavity. May be better not to use too much sample. You could have probably some problems when samples with different size particles are to be compared: be sure that the finest particle samples (at the same amount generally, finest particle samples have bigger volumes...) go also completely into the cavity.

Another approach I used to have may be the one that I was using to call "method of the infinite Sample" and where you put into the ESR tube an Excess of sample, in order that  all the tube part inside and partially outside the cavity was completely filled with sample. This approach did not however give the best results everytime, and did not resolve the problem with different particle size samples.

Dear all,

I characterized ESR spectra of BaTiO3, with few mg powder in tube (up to the mark).

But i have confusion on result.

is my spectra correct or not?

I used conditions like 9.4 GHz, central filed 336 mT with sweep width 5 X 10 mT.

If anyone have clear idea regarding software setup conditions, please explain to me.

how much amplitude and time period, i have to use?

for convenience, i am attached spectra files.

Regards

It is half done as:

[I]It is satisfying to note the PP ESR was recorded at 9.4 GHz.

[II]In all probability( if it contains iron?),the central most intense peak is of Fe3+ (S = 5/2) that corresponds to ±1/2 ↔ ∓ 1/2 transition with geff appxo.2

Now:

[a]Doyou know the particle size? Perhaps, you have not noticed?

[b] If possible, perfom computer stimulation and find whether this central peak splits into at least two lines or not. If yes; find the ratio of their integral intensity[Perhaps computer, itself will give]. There should be a small difference between the “g” values of this doublet. Note it.

[c] You perform PP ESR of 3-4 samples of different sizes; find peaks; their “g”, values; their intensities and make a table of all these paremeters. If the doublet have appreciable difference, then also calculate “A”.

hello....

anyone know how to prepare the sample for nitrosyl compound in vegetable, soil, and water sample for ESR.

another method is used for nitrosyl compound or same method which discuss above messages. 

please clear my dought and give some useful information