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Author Mahamdioua, N. ♦ Amira, A. ♦ Altintas, S. P. ♦ Varilci, A. ♦ Terzioglu, C.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ CURIE POINT ♦ DENSITY ♦ DENSITY OF STATES ♦ DOPED MATERIALS ♦ FERMI LEVEL ♦ GRAIN BOUNDARIES ♦ MAGNETIC FIELDS ♦ MAGNETIC SUSCEPTIBILITY ♦ MAGNETORESISTANCE ♦ PARAMAGNETISM ♦ PHASE TRANSFORMATIONS ♦ POLYCRYSTALS ♦ SIMULATION ♦ SOLIDS ♦ SPACE GROUPS ♦ SPIN ♦ SPIN ORIENTATION ♦ TETRAGONAL LATTICES ♦ TUNNEL EFFECT ♦ YTTRIUM
Abstract We present structural, magnetic and electrical properties of the polycrystalline A-site-deficient yttrium doped double layered manganites La{sub 1.2−x}□{sub 0.2}Y{sub x}Ca{sub 1.6}Mn{sub 2}O{sub 7} (x=0.2, 0.3 and 0.4) prepared by a solid state reaction method. The samples crystallize in the tetragonal structure with the space group I4/mmm. Doping with Y decreases the cell parameters and causes a decrease of the metal-insulator transition temperature. The same evolution with doping is also seen for the deduced Curie temperature from susceptibility curves which present a clear paramagnetic-ferromagnetic transition. The significant positive intrinsic magnetoresistance, shown in all samples, reaches 85% at 122 K under 7 T for 0.3 doped sample and can be attributed to the suppression of spin fluctuations via aligning the spins under external magnetic field, while the extrinsic one is attributed to the inter-grain spin-polarized tunneling across the grain boundaries. The simulation of the resistivity curves in the entire temperature range show that the percolation model is suitable to fit our results. The applied magnetic field increases the density of states near the Fermi level, which is in accordance with the observed decrease of resistivity. - Graphical abstract: Resistivity and magnetoresistance of La{sub 1.2−x}□{sub 0.2}Y{sub x}Ca{sub 1.6}Mn{sub 2}O{sub 7} (x=0.2, 0.3, 0.4). Solid lines correspond to the fitting results. Display Omitted.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-08-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 240


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