Spin Dilution in Frustrated Two-Dimensional s=1/2 Antiferromagnets on a Square Lattice

N. Papinutto; P. Carretta; S. Gonthier; P. Millet

doi:10.1103/PhysRevB.71.174425

paper

Spin Dilution in Frustrated Two-Dimensional s=1/2 Antiferromagnets on a Square Lattice

arXiv:cond-mat/0502452 · doi:10.1103/PhysRevB.71.174425

Abstract

$^{7}$ Li and $^{29}$ Si NMR, $μ$ SR and magnetization measurements in Li $_{2}$ V $_{1 - x}$ OTi $_{x}$ SiO $_{4}$ , for $0 \leq x \leq 0.2$ , are presented. The $x = 0$ compound is a prototype of frustrated two-dimensional Heisenberg antiferromagnet on a square-lattice with competing nearest ( $J_{1}$ ) and next-nearest ( $J_{2}$ ) neighbour exchange interactions. Ti $^{4 +}$ (S=0) for V $^{4 +}$ (S=1/2) substitution yields the spin dilution of the antiferromagnetic layers. The analysis of the magnetization and of the nuclear spin-lattice relaxation rate shows that spin dilution not only reduces the spin-stiffness by a factor $≃ (1 - x)^{2}$ , but also causes the decrease of the effective ratio $J_{2} (x) / J_{1} (x)$ . Moreover, the sublattice magnetization curves derived from zero-field $μ$ SR measurements in the collinear phase point out that, at variance with non-frustrated two-dimensional Heisenberg antiferromagnets, spin dilution affects the low-temperature staggered magnetization only to a minor extent. This observation is supported also by the $x$ dependence of the collinear ordering temperature. The results obtained for the Ti doped samples are discussed in the light of the results previously obtained in the pure $x = 0$ compound and in non-frustrated two-dimensional Heisenberg antiferromagnets with spin-dilution.

8 pages, 9 figures

Spin Dilution in Frustrated Two-Dimensional s=1/2 Antiferromagnets on a Square Lattice

Abstract

References in corpus (13)

Cited by in corpus (17)