Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticles
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In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
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Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticles
- 1. LOGO Synthesis and Charaterization of La1-xSrxMnO3 Perovskite nanoparticles (x from 0 to 0.4) Presenter : Tran Thi Mai – K55 IP Supervisor: Dr. Nguyen Hoang Nam Luu Manh Quynh
- 2. Content Introduction Experimental Results and discussion Conclusion
- 3. I. Introduction 1.1. The perovskite structure ABO3 perovskite has cubic structure and the cubic unit cell has the network parameters is: a = b = c ; At the peak position of the cubic is the cation A that around is the position of the oxygen anion (located in the center of the cubic face). The cation B is located in the center cubic The most important characteristic of the perovskite structure ABO3 is the existence of the octahedral BO6 α = β = γ = 90o
- 4. I. Introduction Crystal structure which can be changed from cubic to other formats such as rhombohedral or orthorhombic when the ion A or ion B is changed by other elements. La1-xSrxMnO3 is a perovskite has the types structure ABO3, in which the La ions are replaced partially by Sr ions. Due to structural differences have caused lattice distortion and make the structure of materials are changed from cubic to other formats.
- 5. I. Introduction 2. Jahn – Teller distortion When the doped or replacement, the ideal perovskite crystal structures will be changed (occurs distortion) Jahn – Teller effects occurs in a metal ions contained the odd number of the electronic in the eg levels. However, this effect also occurs in compounds which have the octahedral structure Jahn – Teller distortion in the perovskite materials When the octahedral structure change will make to the length of association changed according to the axis
- 6. I. Introduction 3. magnetic properties in the perovskite materials system La1-xAxMnO3 LaMnO3 compounds show antiferromagnetic properties due to the super- exchange interaction (SE) between ions Mn3+. When doped ion alkanline metal elements A2+ (Sr2+) into position of ions rare earth La3+, to ensure charge neutralize conditions, the partial charge of ion Mn3+ transfer into ion Mn4+. While the perovskite manganese not doped have dielectric anti –ferromagnetic properties, the appearance of Mn4+ make the electrical conductivity increases and appearance the ferromagnetic properties. When the doped concentration is increased, the conductivity of the material also increases, up to a certain value, the material will good conductivity as metal and to express strong ferromagnetic properties
- 7. I. Introduction 5. The fabrication technology The Solid phase reaction method (ceramic method) The coprecipitation method The hydrothermal method The reaction Milling method The sol – gel method
- 8. I. Introduction The sol – gel method: The process of creating materials by the sol - gel method consists of 4 main stages: Creating solution (sol) Gelled and shaped Drying Conglomeration Các bước tạo vật liệu bằng phương pháp sol – gel The main benefits of sol–gel processing are the high purity and uniform nanostructure achievable at low temperatures.
- 9. II. Experimental 1. The instruments and chemicals chemicals Lanthanum oxide (La2O3) Strontium carbonate (SrCO3) Manganese nitrate (Mn(NO3)2.4H2O) Citric acid (CA.1H2O) Nitric acid (HNO3) instruments Glass, pipet, Thermometer Magnetic stirrer (RH basic KTC) Drying furnace (1350FX – 2E Model) Calcining furnace (CD 1600X CHIDA
- 10. II. Experimental some image of instruments are used in the process Magnetic stirrer (RH basic KTC) Drying furnace (1350FX – 2E Model) Calcining furnace (CD 1600X CHIDA)
- 11. II. Experimental CA Sr(NO3)2 Mn(NO3)2 La(NO3)3 Stirring at 80oC Sol gel compounds xerogel Fabrication process of material by sol – gel method Drying Preheating Heating at 1000o Cat 300o Cat 120o C 2. Fabrication process of material
- 12. II. Experimental 3. Some illustrative photos a) b) c) Figure: a) sol is obtained after stirring at 80o C b) and c) the product respectively obtained after preheating at 300o C and heating at 1000o C
- 13. III. Results and discussion 10 20 30 40 50 60 70 80 0 100 200 300 400 500 x=0.4 Intensity(a.u) 2(degree) (102) (110) (104) (202) (006) (204) (212) (116) (214) (300) (220) (208) XRD patterns of La0.6Sr0.4MnO3 nanoparticles. 1. Analysis of x-ray diffraction diagram (XRD)
- 14. III. Results and discussion 10 20 30 40 50 60 70 80 0 100 200 300 400 500 600 700 800 900 Intensity(a.u) 2(degree) x=0 x=0.1 x=0.2 x=0.3 x=0.4 (102) (110) (104) (202) (006) (204) (212) (116) (214) (300) (220) (208) XRD patterns of La1-xSrxMnO3 nanoparticles with x = 0, 0.1, 0.2, 0.3 and 0.4
- 15. III. Results and discussion Table 1. The lattice parameters of the La1-xCaxMnO3 samples with x from 0 to 0.4 Lattice parameters Volume of cell unit (Å3) Sample a(Å) b(Å) c(Å) x=0 5.48 5.49 7.71 231.96 x=0.1 5.54 5.45 7.92 239.13 x=0.2 5.49 5.50 7.76 234.31 x=0.3 5.49 5.48 7.82 235.26 x=0.4 5.47 5.46 7.91 236.24
- 16. III. Results and discussion From XRD using the Debye – Scherrer formula: Sample d(102) d(110) d(202) d(204) d(212) d(214) x=0 29.6nm 17.5nm 30.9nm 28.4nm 13.0nm 22.5nm 23.7nm x=0.1 28.2nm 17.9nm 25.7nm 28.7nm 14.7nm 21.3nm 22.7nm x=0.2 26.7nm 19.3nm 19.5nm 25.5nm 17.4nm 14.5nm 20.5nm x=0.3 24.7nm 19.4nm 18.4nm 24.6nm 16.5nm 14.1nm 19.6nm x=0.4 27.0nm 22.7nm 19.0nm 25.0nm 15.8nm 15.4nm 20.8nm The size of crystallites of La1-xSrxMnO3 with x from 0 to 0.4 as the table 2. Table 2: Size of crystallites of La1-xSrxMnO3
- 17. III. Results and discussion 2. Analysis of Scanning electron micrographs (SEM), and energy dispersive x – ray spectra (EDS) SEM image and EDS spectra of the sample without doped (LaMnO3)
- 18. III. Results and discussion SEM image and EDS spectra of the sample La0.9Sr0.1MnO3
- 19. III. Results and discussion SEM image and EDS spectra of the sample La0.8Sr0.2MnO3
- 20. III. Results and discussion SEM image and EDS spectra of the sample La0.7Sr0.3MnO3
- 21. III. Results and discussion SEM image and EDS spectra of the sample La0.6Sr0.4MnO3
- 22. III. Results and discussion a) d)c) b) SEM images of La1-xSrxMnO3 with x = 0.1, 0.2, 0.3 and 0.4 annealed at 1000˚C for 2 h shown in order from left to right and top to bottom
- 23. IV. Conclusion In this thesis, we have successfully fabricated La1-xSrxMnO3 perovskite materials that nanoscale by the sol-gel method, doped with Sr ratio from x = 0.1 0.4. The structure analysis shows that the structure of samples is typical perovskite structure and the Sr was successfully doped into sample. The structure of sample have small changes with changing doping ratio x.
- 24. LOGO
Editor's Notes
- In this thesis, I only mention the perovskite compounds fabricated by sol-gel method
- The sol-gel method is a process chain of chemical reactions starting from the sol liquid of precursor are liquid and solid ...the particles sol hydrolysis reaction and condensation to form gel. Gel were dried, calcined to remove the organic matter and the formation of the final product in the solid state
- It can be seen that the XRD pattern of sample with x = 0 clearly shows double peaks which are assigned to rhombohedral structure reflections such as double peak of (220), (208) reflections. When Sr was doped into sample, those peaks were not clearly separated with each other like sample with x = 0, such as the sample with x = 0.4
- XRD patterns indicated that La1-xSrxMnO3 nanoparticles crystallized in typical ABO3 perovskite rhombohedral structure. Thus, we can calculate the lattice constants of the La1-xCaxMnO3 samples with doped ratio x from 0 to 0.4 as table 1.
- the energy – dispersive x-ray spectra (EDS) of the doped composite for x from 0 to 0.4 shows the peaks are La, O, Mn, and Sr, which also supports the presence of Sr2+ in the doped composites
- From the SEM image of the samples with x from 0 to 0.4, It reveals that the particles have particle sizes of much larger than the crystallites sizes that calculated from XRD results. we can see particles conglomerated to clusters. It was not created clear shapes. Particles fairly even and have complicated shape.