I have tried to made some LSMO particles ang got black color particles when sintered the gel at 500C. Does anyone have any idea if the color is right?
Yes; You got it right. Pls. find below the reference and the method of its synthesis reproduced in Toto for your perusal and authentication:
[ Pls look in page 23 of the reference where the color changes which take place during its synthesis are marked in capital letters]
The compound La0.85Sr0.15MnO3 is prepared by sol-gel combustion route. Manganese carbonate (MnCO3), Lanthanum nitrate (LaNO3), Strontium nitrate (Sr (NO3)2) are chosen as the precursors for the synthesis. Glycine is chosen as the fuel for the synthesis. At first a starting solution of MnCO3 is made by mixing with nitric acid (15ml) and then with water (10ml). Then La (NO3)3 and Sr (NO3)2 are taken in stoichiometric ratio and dissolved in distilled water. All the solutions are added to the chelating agent (glycine) in stoichiometric proportion (metal nitrate: glycine=1:1). The colour of the sample is found to be LIGHT BROWN .A continuous slow heating with stirring is maintained over hot plate throughout the experiment. After 4-5 hours, gel is formed without any precipitation due to the evaporation of water. The light brown colour solution changes to the DEEP BROWN colour. After 30 min powder is obtained with vigorous reaction and the gel burnt to form [[ BLACK]] powered.
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LaSrMnO3(LSMO) preparation
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SYNTHESIS AND CHARACTERIZATION OF ... - ethesis
ethesis.nitrkl.ac.in/3601/1/library_upload.pdf
by S MISHRA - 2012 - Related articles
with LSMO having different composition are prepared by solid state route. ..... Lanthanum manganite (LaMnO3) is an antiferromagnetic insulator which when ...
TO FIND
SYNTHESIS AND CHARACTERIZATION OF
SUPERCONDUCTOR COMPOSITE Bi2Sr2Ca1Cu2O8
/La0.85Sr0.15MnO3
A thesis submitted in partial fulfillment for the award of degree in
Master of Science
in
PHYSICS
By
SHREELEKHA MISHRA
ROLL NO: 410PH2130
Under the Guidance of
Dr. Prakash Nath Vishwakarma
Department of Physics
National Institute of Technology, Rourkela
Rourkela-769008, Orissa, India
May-2012.
The author does not give the composition of the system. First, the color will depend on the ratio La:Sr- from almost black to brown. Second: There can be no such compound as LaSrMnO3 - it will crystallize as LaSrMnO4 with layered K2NiF4 type structure. I do not believe you obtained a single phase compound at 500 oC even if you sintered gel. Look at the X-ray. We usually obtain perovskites of this kind after a prolonged sintering at 1400 oC. The time depends on the method of synthesis - ceramic or sol-gel. And the last comment - the color is not a good property for identification of a solid compound (my own experience).
LSMO is typically being used as a ferromagnetic conductors. Ferromagnetic conductors have typical a electron band structure that result in a black colour. Thus, it would have been weird if it was not black or brown
You did not answer to my questions, first about the composition and second about X-ray and the method of synthesis
Chezhina thanks for your concerned but we have not done XRD yet because this was my first trail and I am trying to study in detail. I didn't expected black color so I put the question about the color. I have tried to used pechini method to synthesis this material and the molar ratio of La:Sr was 4
Besselink i think you are right but I wanted to used this for other application but may be not the right material
You must first of all make XRD, It is my experience with perovskites that you cannot predict the color. Once upon a time my best single phase perovskite Sr2AlSbO6 was beige with wite specks (color centers), whereas other samples were beautifully beige, but multiphase.
Hi Sunil
Well I do not know which is the real composition of your LSM system, but in any case, at 500C you may still have carbon (black colour) coming from the pyrolisis of the precursors used (i do not have your details but I suppose that you used several organics-based material). I would suggest you just to do a simple thermal analysis to verify the weight losses and see what happens at each temperature with your material. 500C seems to be very low to get a pure LSM phase, but as Chezhina said use the XRD measurements to verify the purity of your material at each tested temperature.
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