Structural and magnetic states in layered manganites: An expanding view of the phase diagram
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Structural and magnetic states in layered manganites : An expanding view of the phase diagram. / Mitchell, J. F.; Millburn, J. E.; Ling, C.; Argyriou, D. N.; Bordallo, H. N.
In: Materials Research Society Symposium - Proceedings, Vol. 602, 01.12.2000, p. 315-326.Research output: Contribution to journal › Conference article › Research › peer-review
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TY - GEN
T1 - Structural and magnetic states in layered manganites
T2 - Magnetoresistive Oxides and Related Materials
AU - Mitchell, J. F.
AU - Millburn, J. E.
AU - Ling, C.
AU - Argyriou, D. N.
AU - Bordallo, H. N.
PY - 2000/12/1
Y1 - 2000/12/1
N2 - Colossal magnetoresistive (CMR) manganites display a spectacular range of structural, magnetic, and electronic phases as a function of hole concentration, temperature, magnetic field, etc. Although the bulk of research has concentrated on the 3-D perovskite manganites, the ability to study anisotropic magnetic and electronic interactions made available in reduced dimensions has accelerated interest in the layered Ruddlesden-Popper (R-P) phases of the manganite class. The quest for understanding the coupling among lattice, spin, and electronic degrees of freedom (and dimensionality) is driven by the availability of high quality materials. In this talk, we will present recent results on synthesis and magnetic properties of layered manganites from the La2-2xSr1+2xMn2O7 series in the Mn4+-rich regime x > 0.5. This region of the composition diagram is populated by antiferromagnetic structures that evolve from the A-type layered order to G-type "rocksalt" order as x increases. Between these two regimes is a wide region (0.7 < x < 0.9) where an incommensurate magnetic structure is observed. The IC structure joins spin canting and phase separation as a mode for mixed-valent manganites to accommodate FM/AF competition. Transport in these materials is dominated by highly insulating behavior, although a region close to x = 0.5 exhibits metal-nonmetal transitions and an extreme sensitivity to oxygen content. We suggest two possible explanations for this transport behavior at doping just above x=0.5: localization by oxygen defects or charge ordering of Mn3+/Mn4+ sites.
AB - Colossal magnetoresistive (CMR) manganites display a spectacular range of structural, magnetic, and electronic phases as a function of hole concentration, temperature, magnetic field, etc. Although the bulk of research has concentrated on the 3-D perovskite manganites, the ability to study anisotropic magnetic and electronic interactions made available in reduced dimensions has accelerated interest in the layered Ruddlesden-Popper (R-P) phases of the manganite class. The quest for understanding the coupling among lattice, spin, and electronic degrees of freedom (and dimensionality) is driven by the availability of high quality materials. In this talk, we will present recent results on synthesis and magnetic properties of layered manganites from the La2-2xSr1+2xMn2O7 series in the Mn4+-rich regime x > 0.5. This region of the composition diagram is populated by antiferromagnetic structures that evolve from the A-type layered order to G-type "rocksalt" order as x increases. Between these two regimes is a wide region (0.7 < x < 0.9) where an incommensurate magnetic structure is observed. The IC structure joins spin canting and phase separation as a mode for mixed-valent manganites to accommodate FM/AF competition. Transport in these materials is dominated by highly insulating behavior, although a region close to x = 0.5 exhibits metal-nonmetal transitions and an extreme sensitivity to oxygen content. We suggest two possible explanations for this transport behavior at doping just above x=0.5: localization by oxygen defects or charge ordering of Mn3+/Mn4+ sites.
UR - http://www.scopus.com/inward/record.url?scp=0034429852&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:0034429852
VL - 602
SP - 315
EP - 326
JO - Materials Research Society Symposium Proceedings
JF - Materials Research Society Symposium Proceedings
SN - 0272-9172
Y2 - 29 November 1999 through 2 December 1999
ER -
ID: 204464711