Lattice effects and magnetic structure in the layered colossal magnetoresistance manganite La{sub 2{minus}2x}Sr{sub 1+2x}Mn{sub 2}O{sub 7}, x=0.3

Journal Article · Thu Apr 01 00:00:00 EST 1999 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.59.8695· OSTI ID:335614

Argyriou, D N ^[1]; Mitchell, J F ^[2]; Radaelli, P G ^[3]; Bordallo, H N ^[1]; Cox, D E ^[4]; Medarde, M; Jorgensen, J D ^[2]

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1. Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
3. ISIS Facility, Rutherford Appleton Laboratory, Chilton 0X11 0QX (United Kingdom)
4. Brookhaven National Laboratory, Upton, New York 11973 (United States)

We report on the temperature dependence of the crystal and magnetic structure of the layered colossal magnetoresistive manganite, La{sub 2{minus}2x}Sr{sub 1+2x}Mn{sub 2}O{sub 7}, x=0.3. Neutron-diffraction measurements show that the insulator-metal (IM) transition (T{sub IM}) at {approximately}100 K is accompanied by a ferromagnetic (FM) ordering of spins within MnO{sub 6} bilayers ({ital intrabilayer} coupling), but with an antiferromagnetic coupling between neighboring bilayers ({ital interbilayer} coupling). Below T{sub IM}, the Mn spins rotate from {approximately}45{degree} inclination to the {ital c} axis until they are almost parallel to the {ital c} axis at 5 K. Coincident with this spin reorientation, a FM {ital c} axis component develops below 75 K. Evidence from both neutron and synchrotron x-ray-diffraction experiments suggest that the FM {ital c}-axis magnetic moment results from a second layered manganite phase with composition 0.3{approx_lt}x{approx_lt}0.32. This observation emphasizes the need for thorough examination of the homogeneity when measuring bulk properties (e.g., magnetization, transport) of nominally {ital x}=0.3 samples. Associated with the electronic and magnetic transitions, a pronounced lattice response along the {ital c} axis (observed in both phases) signals a transfer of charge into d{sub x{sup 2}{minus}y{sup 2}} orbitals in the low-temperature phase. That the lattice effects here are opposite in sign to those observed in the {ital x}=0.4 layered manganite points to the sensitivity of the spin-lattice-charge coupling to dopant concentration in these reduced-dimensionality manganites. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 335614
• Journal Information: Physical Review, B: Condensed Matter, Vol. 59, Issue 13; Other Information: PBD: Apr 1999
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM COMPOUNDS
STRONTIUM COMPOUNDS
MAGNETORESISTANCE
LANTHANUM OXIDES
STRONTIUM OXIDES
LAYERS
CRYSTAL STRUCTURE
NEUTRON DIFFRACTION
X-RAY DIFFRACTION
CRYSTAL LATTICES
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0065-0273 K
SPIN
MAGNETIZATION