Lanthanum manganate

LaMn03 is a typical perovskite structure material, which belongs to rare earth absorbing material. The rare earth absorbing material has both magnetic loss and dielectric loss, that is, the loss mechanism is diversified. This kind of material has great feasibility as a new kind of microwave absorbing material. Rare earth elements and transition metal elements themselves have special electronic structures and rich electromagnetic optical properties. Manganese doped with rare earth oxides have special electromagnetic properties, is both a dielectric body, is a kind of magnetic materials, and suitable resistivity, it may become a kind of excellent microwave absorbing medium.

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Study on Composite Doped Lanthanum Manganate Ceramics and Its Properties 

(PM) phase transition and paramagnetic-ferromagnetic (PM-FM) phase transition can occur at room temperature, and the infrared emissivity changes with the temperature transition, that is, Phase transition temperature when the infrared emissivity is high, can better heat, and in the phase transition temperature when the infrared emissivity is low, can be better insulation. Doped lanthanum manganate can change the spontaneous regulation of its own emissivity by the temperature change, which makes it hotspot of outdoor thermal control. In this paper, the crystal structure, mechanical properties, infrared emissivity and phase transition temperature of LaMnO3 were studied. The relationship between composition – process – structure – property was explored. The research contents of (1) high purity LaMn1-yByO3 (B = Fe, Ti) powder and La0.825Sr0.175Mn1-yByO3 (B = Fe, Ti) powder were studied. (2) sintering process of high quality LaMn1-yByO3 (B = Fe, Ti) block and La0.825Sr0.175Mn1-yByO3 (B = Fe, Ti) block. (3) The crystal structure was analyzed by XRD, SEM and test equipment. The properties of the crystal structure were analyzed and analyzed, and the properties such as density, hardness, microstructure, room temperature infrared emission rate and phase transition temperature were analyzed and analyzed. The results show that the appropriate process can produce high quality doped LaMnO3, and the doping elements and the doping amount have influence on the crystal structure. The lattice constants a = b ≠ c, a = β = 90, and the lattice constants a = b ≠ c are the crystal structures of Hexagonal R3m [160] doped with Sr, Fe and Sr / Ti in the B- °, γ = 120 °; the unit cell volume is proportional to its lattice constant a, b, and is inversely proportional to its lattice constant c. B is doped with Fe, Ti LaMnO3, mixed with Sr at the A site, reduced unit cell volume and lattice constant. In addition, the room temperature infrared emissivity and phase transition temperature of LaMn1-yByO3 (B = Fe, Ti) and La0.285Sr0.175Mn1-yByO3 (B = Fe, Ti) are related to their unit cell volume, Room temperature infrared emission rate, phase transition temperature is low; the other hand, the cell volume is small, the room temperature infrared emissivity is low, the phase transition temperature is high.

Key words: perovskite lanthanum manganate phase change infrared emissivity