Direct observation of a one-dimensional static spin modulation in insulating La{sub 1.95}Sr{sub 0.05}CuO{sub 4}

Journal Article · Tue Feb 01 04:00:00 EST 2000 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.61.3699· OSTI ID:20215337

Wakimoto, S ^[1]; Birgeneau, R J ^[1]; Kastner, M A ^[1]; Lee, Y S ^[1]; Erwin, R ^[2]; Gehring, P M ^[2]; Lee, S H ^[2]; Fujita, M ^[3]; Yamada, K ^[3]; Endoh, Y ^[4]

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1. Department of Physics and Center for Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2. National Institute of Standards and Technology, NCNR, Gaithersburg, Maryland 20889 (United States)
3. Institute for Chemical Research, Kyoto University, Gokasho, Uji 610-0011, (Japan)
4. Department of Physics, Tohoku University, Sendai 980-8578, (Japan)

We report the results of an extensive elastic neutron-scattering study of the incommensurate (IC) static spin correlations in La{sub 1.95}Sr{sub 0.05}CuO{sub 4}, which is an insulating spin glass at low temperatures. Recent work by Wakimoto et al. has revealed the presence of new two-dimensional satellite peaks in La{sub 1.95}Sr{sub 0.05}CuO{sub 4} at positions rotated by {approx}45 degree sign in reciprocal space from those found in superconducting samples. The present neutron-scattering experiments on the same x=0.05 crystal employ a narrower instrumental Q resolution and thereby have revealed that the crystal has only two, rather than four, orthorhombic twins at low temperatures with relative populations of 2:1. This has made possible the precise characterization of the IC elastic peaks around (1,0,0) and (0,1,0) (orthorhombic notation) in each domain separately. We find that, in a single twin, only two satellites are observed at (1,{+-}0.064,L){sub ortho} and (0,1{+-}0.064,L){sub ortho}, that is, the modulation vector is only along the orthorhombic b{sup *} axis. This demonstrates unambiguously that La{sub 1.95}Sr{sub 0.05}CuO{sub 4} has a one-dimensional rather than two-dimensional static diagonal spin modulation at low temperatures, consistent with certain stripe models. From the L dependence we conclude that the spin correlations are predominantly two dimensional. We have also reexamined the x=0.04 crystal that previously was reported to show a single commensurate peak. By mounting the sample in the (H,K,0) zone, we have discovered that the x=0.04 sample in fact has the same IC structure as the x=0.05 sample. The incommensurability parameter {delta} for x=0.04 and 0.05, where {delta} is the distance from (1/2,1/2) in tetragonal reciprocal lattice units, follows the linear relation {delta}{approx_equal}x. These results demonstrate that the insulator to superconductor transition in the underdoped regime (0.05{<=}x{<=}0.06) in La{sub 2-x}Sr{sub x}CuO{sub 4} is coincident with a transition from diagonal to collinear static stripes at low temperatures thereby evincing the intimate coupling between the one-dimensional spin density modulation and the superconductivity. (c) 2000 The American Physical Society.

• OSTI ID: 20215337
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 5 Vol. 61; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COPPER OXIDES
CRITICAL TEMPERATURE
DOMAIN STRUCTURE
ELECTRICAL INSULATORS
EXPERIMENTAL DATA
HIGH-BETA PLASMA
LANTHANUM OXIDES
MAGNETIC PROPERTIES
NEUTRON DIFFRACTION
ORTHORHOMBIC LATTICES
PHASE TRANSFORMATIONS
SPIN GLASS STATE
STRONTIUM OXIDES
THEORETICAL DATA
TRANSITION TEMPERATURE