Observation of the Neel state in doped CuGeO<sub>3</sub>
J -G Lussier; S M Coad; D F McMorrow; D McK Paul; J -G Lussier; Dept. of Solid State Phys., Riso Nat. Lab., Roskilde, Denmark; S M Coad; Dept. of Solid State Phys., Riso Nat. Lab., Roskilde, Denmark; D F McMorrow; Dept. of Solid State Phys., Riso Nat. Lab., Roskilde, Denmark; D McK Paul; Dept. of Solid State Phys., Riso Nat. Lab., Roskilde, Denmark
Журнал:
Journal of Physics: Condensed Matter
Дата:
1995-06-19
Аннотация:
The effect of doping on the spin-Peierls (SP) transition in single crystals of CuGeO<sub>3</sub> has been investigated using neutron scattering techniques and susceptibility measurements. When the Cu<sup>2+</sup> site is partly substituted by either Zn<sup>2+</sup> (4%) or Ni<sup>2+</sup> (1.5%) the SP is suppressed, and a long-range Neel state develops below T<sub>N</sub>=2.8 K (Zn) and T<sub>N</sub>=2.2 K (Ni) with a wave vector of (0, 1, 1/2 ). This observation contrasts with earlier reports of a spin glass transition in the doped compounds in the same temperature range. Our results also indicate that the reported Neel state in the nominally pure compound results from impurities. Preliminary measurements of the Zn-doped sample show that the gap that opens in the magnetic excitations below T<sub>SP</sub> collapses in the doped compound.
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