Effect of Manganese Addition on the Structure, Magnetic Properties and Microwave Absorption of La0.8Ba0.2MnxFe?(1-x)Ti?(1-x)O3

3rd International Seminar On Sciences "Sciences On Precision And Sustainable Agriculture"

Adi, W.A.^1 ; Indro, M.N.^2 ; Kusumastuti, A.A.^2

Center for Science and Technology of Advanced Materials, National Nuclear Energy Agency, Indonesia^1

Departement of Physics, Bogor Agricultural University, Indonesia^2

关键词: Double exchange mechanism;    ferromagnetic;    Ferromagnetic behaviour;    Ferromagnetic properties;    La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3;    Microwave absorbers;    Monoclinic crystal structure;    phase;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/58/1/012047/pdf
DOI  :  10.1088/1755-1315/58/1/012047

来源: IOP

【 摘 要 】

We have carried out modification of La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3(x = 0.1 - 0.8) magnetic materials by wet milling method. Raw materials of La2O3, BaCO3, Fe2O3, TiO2and MnCO3were mixed according to stoichiometry calculation for each composition. The mixture was milled for 5 hours and then sintered at 1000 °C for 5 hours. The refinement results by X-ray diffraction pattern shows that the increasing Mn composition enhances the mass fraction of La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3phase which has the same structure as LaMnO3. For x = 0.8 a single phase of LaMnO3was formed. The single phase has a crystal monoclinic crystal structure with space group of I 1 2 / a 1, with lattice parameters given by a = 5.519(5) Å, b = 5.5537(5) Å and c = 7.8176(9) Å, α = γ = 90oand β = 90.345(6)o, V = 239.64(3) Å3, ρ = 6.463 gr.cm-3, wRp = 5.96, and χ2(chi-squared) = 1.17. The hysteresis curve shows that the sample with composition x = 0.8 produces ferromagnetic behaviour at room temperature. The ferromagnetic properties arise due to the mixed valence of Mn3+and Mn4+ions through a double exchange mechanism. The results of the microwave absorption indicated that there was a broadening of absorption peak frequency at 9.9 GHz. The reflection loss (RL) increases with the increasing of LaMnO3phase. For x = 0.8 we have the best of RL where the microwave absorption was calculated reaching 95% at the highest peak frequency with a thickness of 1.5 mm. Thus we have been successful in creating a single phase of La0.8Ba0.2MnxFe1/2(1-x)Ti1/2(1-x)O3with application as a microwave absorber.