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MANGANITE (Manganese Oxide Hydroxide) Manganite was a valuable manganese ore when it was found in plentiful deposits. If manganite is massive, it is difficult to distinguish it from other manganese minerals. Luster is metallic to dull in weather specimens. mineral.galleries.com /minerals/oxides/manganit/manganit.htm   (261 words)

Rocks & Minerals: Manganite   (Site not responding. Last check: 2007-10-28) Manganite is monoclinic 2/m, occasionally occurring in well-developed pseudo-orthorhombic prismatic crystals striated parallel with [001], which have been reported in lengths up to 7.5 cm. Manganite has commonly altered to other manganese oxides such as pyrolusite, braunite, and hausmannite, and pseudomorphs of manganite after calcite are relatively common. Crystalline manganite, generally in radial and parallel fibrous masses, is reported by Paris (1994) from mines in Bradley, Carter, Cocke, Johnson, and Unicoi Counties, Tennessee. www.findarticles.com /p/articles/mi_m0GDX/is_4_74/ai_58915138   (1248 words)

[No title]   (Site not responding. Last check: 2007-10-28) Manganite was known in ancient times and was used in the decolorization of glass, according to ancient historians. Manganite is usually found in association with pyrolusite and psilomelane (manganese oxide), often in deposits with admixtures of iron. Manganite commonly forms columnar crystals grouped in druses or it develops crusts and delicately acicular masses. www12.brinkster.com /177272/mybaddir/magnetite.asp   (165 words)

Rocks & Minerals : Manganite. @ HighBeam Research   (Site not responding. Last check: 2007-10-28) It is not often represented in dealers' stocks and, when present, is always expensive and likely to be recycled from an "old" collection or to have been acquired through exchange with a museum, as is the case of this specimen. Manganite is a submetallic mineral that typically varies in color from dark steel-gray to fl. However, in transmitted light, like many apparently opaque minerals, it is red-brown on thin edges and, in reflected light, shows red internal reflections under the microscope; thus, predictably, the streak is reddish-brown to fl. static.highbeam.com /r/rocksampminerals/july011999/manganite   (189 words)

Los Alamos National Laboratory (LANL): Scientists provide new understanding of manganites In a paper published in the March 25 issue of the scientific journal Nature, Los Alamos scientists Ken Ahn, Turab Lookman and Alan Bishop theorize that the presence of metallic and insulating phases in perovskite manganite are strain-induced, caused by pressures applied to the mineral's structure lattice during formation. Perovskite manganite, or manganite, is a steel-gray or fl mineral that occurs as crystals of manganese ore. Perovskite refers to the cubic crystal form the manganite may take. In 1994, a more powerful magnetoresistance phenomenon known as "colossal magnetoresistance" (CMR) was discovered in manganite and other materials with perovskite crystalline structure that made them appealing to industry as potential materials for use in a new generation of miniature magnetic read heads for computer disk drives. www.lanl.gov /news/index.php/fuseaction/home.story/story_id/2075   (621 words)

[No title] The manganites show tw o different forms of colossal magnetoresistance (CMR): that wh ich is associated with very narrow domain walls in polycrystalline samples with grain boundaries, and that associated with magnetic ordering near to the transition temperature. The phase diagram of the manganites as a function of doping shows that the value of T{\sub c} is a strong function of the electron doping. It is important to note that the effect of the interface propagates across the width of the manganite as a result of the substantial susceptibility around the Curie point.{\b\i \par }\pard \qj\fi567\sb120\widctlpar\hyphpar0 The practical embodiment of the heterostructure raises a number of issues, some of which are still to be resolved. www.tcd.ie /Physics/People/Michael.Coey/oxsen/articles/gibbs97/gibbs97.rtf   (3286 words)

Journal of Electronic Materials: Enhancement of Ferromagnetism in the Colossal-Magnetoresistance Layered Manganite ... Jonker and van Santcn1 were the first to report the fascinating electrical and magnetic properties of rare-earth manganites as early as 1950. In 1993, von Helmholt et al.6 reported the dramatic changes in many physical properties of these rare-earth-based (trivalent) manganites when doped with an alkaline-earth metal (or a divalent ion), such as Ca or Ba, and was followed by Jin et al.7 who showed remarkable magnetoresistance (MR) effects near Tc in optimized thin films. Although there are many systematic studies on the hole-doped manganites that vary the concentration of the alkaline earth ions that affects the Mn^sup 3+^/Mn^sup 4+^ ratio, there are very few studies on the doping at the Mn site in these systems. www.findarticles.com /p/articles/mi_qa3776/is_200411/ai_n9462782   (1313 words)

manganite.htm   (Site not responding. Last check: 2007-10-28) Description: Manganite is a lustrous fl to steel gray mineral formed in hydrothermal veins or as a groundwater precipitate. IRON COUNTY: Manganite was found as lustrous striated tabular crystals in clusters lining vugs up to 1 foot across in the iron formation at the Montreal Mine, NE NE sec. The manganite also occurred as radial fibrous to asbestiform crystals in the vugs. www.uwrf.edu /~wc01/manganite.htm   (62 words)

Surface Modification of Perovskite Manganite Thin Films using Atomic Force Microscopy CMR manganite materials have been demonstrated to be useful for a variety of technological applications including magnetic sensors and bolometric infrared detectors. We find that the feature heights are considerably larger on manganite thin film surfaces than those induced on silicon surface under similar conditions. Additionally, the speed of reproducible writing is also found to be significantly higher on the manganite films. www.nsti.org /Nanotech2006/showabstract.html?absno=949   (245 words)

Theses from Umeå University: 253 - Chemical Processes at the Water-Manganite (?-MnOOH) Interface The chelating rings between the Cd(II) and glyphosate, found in aqueous complexes, are maintained at the surface, and the ternary complex is bound to the surface through the phosphonate group of the ligand. This thesis summarises six papers in which the surface chemistry of synthetic manganite has been investigated with respect to surface acid-base properties, dissolution, and adsorption of Cd(II) and the herbicide N-(phosphonomethyl)glycine (glyphosate, PMG). The adsorption and co-adsorption of Cd(II) and glyphosate at the manganite surface was studied at pH>6. www.diva-portal.se /umu/theses/abstract.xsql?dbid=253   (741 words)

Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations The rate of Mn{sup 3+} reduction was optimal at pH of 7.0 and 26 C consistent with an enzymatic reaction. In addition the rates of reduction were in proportion to the amount of manganite added, but nearly independent of the cell concentration present (e.g., cell number had only a small effect on the rate of Mn{sup 3+} reduction at early stages of growth) suggesting that surface properties were dictating the rates of metal reduction. When manganite crystals were dried and gold coated, and viewed by standard scanning electron microscopy (SEM), abundant bacteria could be seen on the surface of the metal oxide in a thin biofilm-like layer. www.osti.gov /energycitations/product.biblio.jsp?osti_id=329219   (442 words)

cmr   (Site not responding. Last check: 2007-10-28) A special type of manganese oxides, manganite perovskites, attracted considerable attention recently due to discovery of the so- called "colossal" magnetoresistance (CMR) in this family of compounds in 1993. In manganites, the MR was found to be extremily large. For example, in lanthanum manganites at 77 K the MR is by 3 orders of magnitude greater than for the previously obtained record in multilayered Fe-Cr films. www.physics.rutgers.edu /~gersh/cmr.htm   (729 words)

Title page for ETD 385   (Site not responding. Last check: 2007-10-28) Chapter 1 briefly overviews the studies of the colossal magnetoresistance in the manganite materials, and the low-field magnetoresistance in manganite thin films. Chapter 2 describes the experimental methods to prepare the high quality manganite thin films, i.e., the pulse-laser deposition technique, and the characterization of the structural, electrical and magnetic properties of the films using X-ray diffraction (XRD), atomic force microscopy (AFM) and other measurements. The large LFMR is strongly dependent on the film thickness, temperature and the composition of the manganites. etda.libraries.psu.edu /theses/approved/PSUonlyIndex/ETD-385   (761 words)

James N. Eckstein, UIUC Physics   (Site not responding. Last check: 2007-10-28) When the manganite is the most conducting, however, its is possible to obtain tunneling spectra that are predominantly due to the tunnel junction. We propose that the metallic tunneling obtained in these structures grown with epitaxial and in-situ interfaces is due to a metallic and ungapped density of states at the Fermi energy in the manganites. We will discuss the extent to which "colossal" magnetoresistance in manganite spin-valves can be preserved at higher temperatures and low fields by atomic layer engineering of the interface. www.physics.uiuc.edu /People/Faculty/profiles/Eckstein   (991 words)

UMI ProQuest Digital Dissertations - Full Citation & Abstract Kinetic and equilibrium studies were conducted with catechol and Pb(II) on birnessite, manganite, and pyrolusite using electron paramagnetic resonance (EPR) spectroscopy, diffuse reflectance spectroscopy (DRS), and x-ray absorption spectroscopy (XAS). The surface complex formed between birnessite and manganite with catechol was confirmed for the first time by DRS as inner-sphere based on the ligand-to-metal-charge transfer bands at 10812 cmandndash;1 and 12674 cmandndash;1. Lead adsorbed as an inner-sphere surface complex on both birnessite and manganite with no evidence to suggest oxidation or surface precipitation as operative sorption mechanisms based on XAFS spectra. ag.udel.edu /soilchem/matochaabs.html   (334 words)

Manganite, rock, crystal, mineral, gem stone, birth stones - mineralgallery Crystals are usually grouped into tight bundles and columnar, massive and fibrous forms are also known. Manganite was a valuable manganese ore when it was found in plentiful deposits. If Manganite is massive, it is difficult to distinguish it from other manganese minerals. www.mineralgallery.co.za /manganite.htm   (202 words)

-MRS- Carriers injected into the superconductor from the half-metallic manganite in bilayer heterostructures were found to drive the superconductor out of equilibrium, resulting in a suppression of the critical current and transition temperature. The variations in the magnetic ordering, transport and structure in the Mn and Co perovskite oxides are a manifestation of the interaction among the spin, charge and lattice degrees of freedom, modulated by doping, temperature, chemical or hydrostatic pressure and a magnetic field. The phonon band shifts due to the variation of the tolerance factor and isotope exchange are discussed in the frame of the virial energy exchange between normal vibration mode (without charge transfer) and resonance vibration of the O atoms in the double-well potential (with charge transfer). lucy.mrs.org /meetings/fall98/absbook/AbstractBookP.html   (15935 words)

MANGANITE - where to best buy Sorry, you must be logged in before you can rate this lens. Manganite is a mineral with composition is manganese oxide-hydroxide. The name manganite was given by W. Flaidinger in 1827. www.squidoo.com /MANGANITE/?x=1&adult=false&ufg=false   (224 words)

CISE Seminars - Columbia Center for Integrated Science & Engineering The myriad phase transitions found in the manganites are classic examples of the effects of coupled degrees of freedom in strongly correlated materials. In the case of manganites, the ionic sites of interest are the Mn ions and their strongly correlated 3d valence electrons. The challenge to testing this picture has been the absence of a probe that can directly observe the orbital order: after all, this requires a probe which can see that the shape of the electron cloud around one Mn site is different from its neighbor's. www.cise.columbia.edu /seminars   (750 words)

MRSEC main page Manganites are mixed-valent oxides of manganese that display interesting physical properties such as “electronic” phase separation, and metallic phases with almost fully spin polarised conduction electrons. In a phase separated thin film manganite device, magnetic domain walls can be created in ferromagnetic percolating pathways. This demonstrates micron-scale spin coherence in the nanotube, and spin injection between an inorganic half-metallic crystal and the organic molecule. www.cise.columbia.edu /mrsec/mrsecseminar_main.php?show=all   (9293 words)

March 2002 News Manganite materials exhibit colossal magnetoresistance, or CMR, which is a dramatic increase in the resistance of the material in the presence of a magnetic field. The overview of manganite thin films it provides covers several important topics, and provides the reader with some areas that have yet to be explored. The supporters from the first quarter of the 2002 fiscal year who wish to be listed, grouped according to their appropriate category, and with the number of years that they have contributed to RIC in parenthesis, are listed below. www.external.ameslab.gov /ric/Mar02News.html   (4987 words)

American Elements: Lanthanum Strontium Manganite Supplier & Tech Info Lanthanum Strontium Manganite has an excellent thermal expansion match with Yttria Stabilized Zirconia (YSZ) electrolytes. Lanthanum Strontium Manganite belongs to a class of "A" site and "B" site doped perovskite structures with these properties. Lanthanum Strontium Manganite is available as a powder for tape casting, air spray/thermal spray/plasma spray, extrusion and sputtering fuel cell applications and as an ink for screen printing. www.americanelements.com /lsm.html   (284 words)

Nickel and copper accumplation as essential elements in 10-Å manganite of deep-sea manganese nodules Nickel and copper accumplation as essential elements in 10-Å manganite of deep-sea manganese nodules should not be compared directly with each other.] However, there have been few experimental studies of the mechanism of accumulation and the crystallochemistry of these elements in 10-Å manganite of manganese nodules, although many experimental studies of adsorption of metals to natural and synthetic manganese and iron oxides have been made I have now investigated the mechanism of accumulation of nickel and copper in manganese nodules by synthesising 10-Å manganite and comparing the composition with that shown by microscopic and electron microprobe analyses of marine 10-Å manganite. www.nature.com /nature/journal/v279/n5712/abs/279411a0.html   (289 words)

Lawrence Berkeley National Laboratory Library   (Site not responding. Last check: 2007-10-28) The sorption of Pu(VI) and Pu(V) onto manganite (MnOOH) and Hausmannite (Mn3O4) was studied at pH 5. Manganite sorbed 21-24% from a 1x10-4 M plutonium solution and the hausmannite removed between 43-66% of the plutonium. Between 53-59% of the plutonium was present as Pu(IV) in the manganite samples while 55-61% of the plutonium complexed to the hausmannite had also been reduced to Pu(IV). www-library.lbl.gov /lbnl_reports/DDW?W=DOC_NUMBER='LBNL-47777'   (203 words)

Manganite - complete list of mineral names Magnetic ground states of a layered manganite crystal Magnetic ground states of a layered manganite crystal We extend the model Hamiltonian of cubic perovskite manganites to a layered manganite system by considering the anisotropy in charge... metallic and insulating phases in perovskite manganite are strain-induced, caused by pressures... Perovskite manganite, or manganite, is a steel-gray or... www.absoluterocknet.com /complete_list_of_mineral_and_crystal_names/Manganite.asp   (502 words)

TVoltage-controlled colossal magnetoresistance in manganite/normal-metal heterostructures Ziese M, Sena S, Shearwood C, ...   (Site not responding. Last check: 2007-10-28) It is well established that the resistivity of the manganites is a strong function of the magnetization. Near the ferromagnetic ordering temperature, colossal changes in the resistivity are seen in applied fields of several Tesla; such fields are too large for a number of potential applications. Implications of the interface resistance on spin injection from classical ferromagnets into manganites are discussed. www.shef.ac.uk /physics/research/theory/papers/gag5.html   (188 words)

Manganite Mineral Data Comments: Pinkish to nearly white earthy sudoite with dark manganite. Comments: Opaque white fibrous vaterite with red defernite and fl manganite. Gray white with brownish tint with blood red internal reflections. webmineral.com /data/Manganite.shtml   (276 words)

Definition of manganite - Merriam-Webster Online Dictionary Learn more about "manganite" and related topics at Britannica.com Find more about "manganite" instantly with Live Search See a map of "manganite" in the Visual Thesaurus www.webster.com /dictionary/manganite   (60 words)

Selected Specimens This specimen consists of interesting rounded masses of brilliant manganite crystals on a bed of an earlier generation of dark-dull manganite or perhaps, some other manganese dominant species. A cavity on the top of this matrix of coarse manganite, manganese and iron oxides is lined with splendent crystals of manganite and a single 7mm quartz xls. The manganites are unusual for this location and very nice as you can see from the close-up. www.davidkjoyceminerals.com /htmfiles/thumbpg.asp?TitleID=30   (338 words)

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