Lanthanum manganite

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Lanthanum manganite
Identifiers
3D model (JSmol)
Properties
LaMnO3
Molar mass 241.84 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Lanthanum manganite is an inorganic compound with the formula LaMnO3, often abbreviated as LMO. Lanthanum manganite is formed in the perovskite structure, consisting of oxygen octahedra with a central Mn atom. The cubic perovskite structure is distorted into an orthorhombic structure by a strong Jahn–Teller distortion of the oxygen octahedra.[2]

LaMnO3 often has lanthanum vacancies as evidenced by neutron scattering. For this reason, this material is usually referred as LaMnO3+ẟ. These vacancies generate a structure with a rhombohedral unit cell in this perovskite. A temperatures below 140 K, this LaMnO3+ẟ semiconductor exhibit a ferromagnetic order.[3]

Synthesis[]

Lanthanum manganite can be prepared via solid-state reactions at high temperatures, using their oxides or carbonates.[4] An alternative method is to use and manganese nitrate as raw materials. The reaction occurs at high temperature after the solvents are vaporized.[5]

Lanthanum manganite alloys[]

Lanthanum manganite is an electrical insulator and an A-type antiferromagnet. It is the parent compound of several important alloys, often termed rare-earth manganites or colossal magnetoresistance oxides. These families include lanthanum strontium manganite, lanthanum calcium manganite and others.

In lanthanum manganite, both the La and the Mn are in the +3 oxidation state. Substitution of some of the La atoms by divalent atoms such as Sr or Ca induces a similar amount of tetravalent Mn4+ ions. Such substitution, or doping can induce various electronic effects, which form the basis of a rich and complex electron correlation phenomena that yield diverse electronic phase diagrams in these alloys.[6]

See also[]

References[]

  1. ^ Macintyre, Jane E. (1992). Dictionary of Inorganic Compounds. CRC Press. p. 3546. ISBN 9780412301209.
  2. ^ S. Satpathy; et al. (1996). "Electronic Structure of the Perovskite Oxides: La1−xCaxMnO3". Physical Review Letters. 76 (6): 960–963. Bibcode:1996PhRvL..76..960S. doi:10.1103/PhysRevLett.76.960. hdl:10355/9487. PMID 10061595.
  3. ^ J. Ortiz, L. Gracia, F. Cancino, U. Pal; et al. (2020). "Particle dispersion and lattice distortion induced magnetic behavior of La1−xSrxMnO3 perovskite nanoparticles grown by salt-assisted solid-state synthesis". Materials Chemistry and Physics. 246: 122834. doi:10.1016/j.matchemphys.2020.122834.CS1 maint: multiple names: authors list (link)
  4. ^ Bockris, John O'M.; Otagawa, Takaaki (1983). "Mechanism of oxygen evolution on perovskites". The Journal of Physical Chemistry. 87 (15): 2960–2971. doi:10.1021/j100238a048. ISSN 0022-3654.
  5. ^ Liu, Yuxi; Dai, Hongxing; Du, Yucheng; Deng, Jiguang; Zhang, Lei; Zhao, Zhenxuan; Au, Chak Tong (2012). "Controlled preparation and high catalytic performance of three-dimensionally ordered macroporous LaMnO3 with nanovoid skeletons for the combustion of toluene". Journal of Catalysis. 287: 149–160. doi:10.1016/j.jcat.2011.12.015. ISSN 0021-9517.
  6. ^ Dagotto, E. (14 March 2013). Nanoscale Phase Separation and Colossal Magnetoresistance. Springer. ISBN 978-3-662-05244-0.


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