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Muon-spin-rotation measurements in infinite-layer and infinite-chain cuprate antiferromagnets: Ca[sub 0. 86]Sr[sub 0. 14]CuO[sub 2] and Sr[sub 2]CuO[sub 3]

Journal Article · · Physical Review, B: Condensed Matter; (United States)
; ; ; ; ;  [1];  [2];  [3]
  1. Department of Physics, Columbia University, New York, New York 10027 (United States)
  2. Superconductivity Research Laboratory, International Superconductivity Technology Center, 1-10-13, Shinonome, Koto-ku, Tokyo 135 (Japan)
  3. Department of Applied Physics, Faculty of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113 (Japan)
We have performed zero-field muon-spin-rotation [mu]Sr measurements of the infinite-layer'' cuprate compound Ca[sub 0.86]Sr[sub 0.14]CuO[sub 2] and the infinite chain'' system Sr[sub 2]CuO[sub 3]. A spontaneous magnetic field from the ordered Cu moments is observed below [ital T][sub [ital N]]=540[plus minus]5 K in Ca[sub 0.86]Sr[sub 0.14]CuO[sub 2]: below [ital T]=360 K, we observe muon-spin precession with a frequency [nu]([ital T][r arrow]0=16) MHz (corresponding to a local field of 1.2 kG). The precession signal is replaced by a rapid depolarization above [ital T]=360 K due to the onset of muon diffusion. The hopping rate followed an Arrhenius law, with an activation energy of [ital E][sub [ital a]]=0.39(1) eV. The sublattice magnetization [ital M][sub [ital s]], proportional to [nu]([ital T]), showed a slower decay with increasing temperature in Ca[sub 0.86]Sr[sub 0.14]CuO[sub 2], compared with that observed in La[sub 2]CuO[sub 4] and Sr[sub 2]CuO[sub 2]Cl[sub 2], indicating that a wider CuO[sub 2]-layer separation results in a more two-dimensional magnetic behavior. In the infinite-chain system Sr[sub 2]CuO[sub 3], the onset of magnetic order was found at [ital T][similar to]5 K with a local field of [similar to]30 G at the muon site at [ital T][r arrow]0. The exchange interaction, inferred from susceptibility measurements is on the order of 10[sup 3] K, implying a remarkable suppression of the ordering temperature with [ital k][sub [ital B]T[ital N]]/[ital J][le]0.01 in Sr[sub 2]CuO[sub 3]. These results demonstarate clear signatures of low-dimensional magnetic behavior in the CuO chains.
OSTI ID:
5429723
Journal Information:
Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:17; ISSN PRBMDO; ISSN 0163-1829
Country of Publication:
United States
Language:
English