Lanthanum manganite

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Lanthanum manganite
LaMnO3 unit cell.png
Identifiers
3D model (JSmol)
  • InChI=1S/La.Mn.3O/q2*+3;3*-2
    Key: JBZIKYYYMXDQRI-UHFFFAOYSA-N
  • [La+3].[Mn+3].[O-2].[O-2].[O-2]
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).

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]

Contents

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 lanthanum nitrate 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

Related Research Articles

<span class="mw-page-title-main">Perovskite (structure)</span> Type of crystal structure

A perovskite is any material with a crystal structure following the formula ABX3, which was first discovered as the mineral called perovskite, which consists of calcium titanium oxide (CaTiO3). The mineral was first discovered in the Ural mountains of Russia by Gustav Rose in 1839 and named after Russian mineralogist L. A. Perovski (1792–1856). 'A' and 'B' are two positively charged ions (i.e. cations), often of very different sizes, and X is a negatively charged ion (an anion, frequently oxide) that bonds to both cations. The 'A' atoms are generally larger than the 'B' atoms. The ideal cubic structure has the B cation in 6-fold coordination, surrounded by an octahedron of anions, and the A cation in 12-fold cuboctahedral coordination. Additional perovskite forms may exist where either/both the A and B sites have a configuration of A1x-1A2x and/or B1y-1B2y and the X may deviate from the ideal coordination configuration as ions within the A and B sites undergo changes in their oxidation states.

Colossal magnetoresistance (CMR) is a property of some materials, mostly manganese-based perovskite oxides, that enables them to dramatically change their electrical resistance in the presence of a magnetic field. The magnetoresistance of conventional materials enables changes in resistance of up to 5%, but materials featuring CMR may demonstrate resistance changes by orders of magnitude.

Molybdenum trioxide describes a family of inorganic compounds with the formula MoO3(H2O)n where n = 0, 1, 2. The anhydrous compound is produced on the largest scale of any molybdenum compound since it is the main intermediate produced when molybdenum ores are purified. The anhydrous oxide is a precursor to molybdenum metal, an important alloying agent. It is also an important industrial catalyst. It is a yellow solid, although impure samples can appear blue or green.

The Jahn–Teller effect is an important mechanism of spontaneous symmetry breaking in molecular and solid-state systems which has far-reaching consequences in different fields, and is responsible for a variety of phenomena in spectroscopy, stereochemistry, crystal chemistry, molecular and solid-state physics, and materials science. The effect is named for Hermann Arthur Jahn and Edward Teller, who first reported studies about it in 1937.

<span class="mw-page-title-main">Manganate</span> Chemical compound

In inorganic nomenclature, a manganate is any negatively charged molecular entity with manganese as the central atom. However, the name is usually used to refer to the tetraoxidomanganate(2−) anion, MnO2−
4
, also known as manganate(VI) because it contains manganese in the +6 oxidation state. Manganates are the only known manganese(VI) compounds.

Rhenium trioxide or rhenium(VI) oxide is an inorganic compound with the formula ReO3. It is a red solid with a metallic lustre that resembles copper in appearance. It is the only stable trioxide of the Group 7 elements (Mn, Tc, Re).

<span class="mw-page-title-main">Half-metal</span>

A half-metal is any substance that acts as a conductor to electrons of one spin orientation, but as an insulator or semiconductor to those of the opposite orientation. Although all half-metals are ferromagnetic, most ferromagnets are not half-metals. Many of the known examples of half-metals are oxides, sulfides, or Heusler alloys. Types of half-metallic compounds theoretically predicted so far include some Heusler alloys, such as Co2FeSi, NiMnSb, and PtMnSb; some Si-containing half–Heusler alloys with Curie temperatures over 600 K, such as NiCrSi and PdCrSi; some transition-metal oxides, including rutile structured CrO2; some perovskites, such as LaMnO3 and SeMnO3; and a few more simply structured zincblende (ZB) compounds, including CrAs and superlattices. NiMnSb and CrO2 have been experimentally determined to be half-metals at very low temperatures.

Lanthanum strontium cobalt ferrite (LSCF), also called lanthanum strontium cobaltite ferrite is a specific ceramic oxide derived from lanthanum cobaltite of the ferrite group. It is a phase containing lanthanum(III) oxide, strontium oxide, cobalt oxide and iron oxide with the formula La
x
Sr
1-x
Co
y
Fe
1-y
O
3
, where 0.1≤x≤0.4 and 0.2≤y≤0.8.

<span class="mw-page-title-main">Lanthanum strontium manganite</span>

Lanthanum strontium manganite (LSM or LSMO) is an oxide ceramic material with the general formula La1−xSrxMnO3, where x describes the doping level.

<span class="mw-page-title-main">Manganese(III) oxide</span> Chemical compound

Manganese(III) oxide is a chemical compound with the formula Mn2O3. It occurs in nature as the mineral bixbyite (recently changed to bixbyite-(Mn)) and is used in the production of ferrites and thermistors.

Manganite a mineral composed of manganese oxide-hydroxide, MnO(OH).

<span class="mw-page-title-main">Calcium copper titanate</span> Chemical compound

Calcium copper titanate (also abbreviated CCTO, for calcium copper titanium oxide) is an inorganic compound with the formula CaCu3Ti4O12. It is noteworthy for its extremely large dielectric constant (effective relative permittivity) of over 10,000 at room temperature.

George Ogurek Zimmerman, was a Polish-born American scientist, researcher, inventor, professor of physics and physics department chair at Boston University. Zimmerman achieved his PhD in solid state physics in 1963 at Yale University and came to Boston University in the fall of 1963.

LSAT is the most common name for the inorganic compound lanthanum aluminate - strontium aluminium tantalate, which has the chemical formula (LaAlO3)0.3(Sr2TaAlO6)0.7 or its less common alternative: (La0.18Sr0.82)(Al0.59Ta0.41)O3. LSAT is a hard, optically transparent oxide of the elements lanthanum, aluminium, strontium and tantalum. LSAT has the perovskite crystal structure, and its most common use is as a single crystal substrate for the growth of epitaxial thin films.

Lanthanum aluminate is an inorganic compound with the formula LaAlO3, often abbreviated as LAO. It is an optically transparent ceramic oxide with a distorted perovskite structure.

A complex oxide is a chemical compound that contains oxygen and at least two other elements. Complex oxide materials are notable for their wide range of magnetic and electronic properties, such as ferromagnetism, ferroelectricity, and high-temperature superconductivity. These properties often come from their strongly correlated electrons in d or f orbitals.

Lanthanum ytterbium oxide is a solid inorganic compound of lanthanum, ytterbium and oxygen with the chemical formula of LaYbO3. This compound adopts the perovskite structure.

Lanthanum cobaltite is a perovskite with chemical formula LaCoO3. As a solid, the structure LaCoO3, will exist as rhombohedral material at room temperature with ferroelastic properties; though at temperatures above ~900 °C a phase transition to a cubic lattice occurs.

<span class="mw-page-title-main">Mixed conductor</span>

Mixed conductors, also known as mixed ion-electron conductors(MIEC), are a single-phase material that has significant conduction ionically and electronically. Due to the mixed conduction, a formally neutral species can transport in a solid and therefore mass storage and redistribution are enabled. Mixed conductors are well known in conjugation with high-temperature superconductivity and are able to capacitate rapid solid-state reactions.

This is an incomplete list of works by John B. Goodenough. His academic output has been described as "prolific".

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" (PDF). 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. S2CID   213205110.{{cite journal}}: 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.