Site-dilution in the quasi-one-dimensional antiferromagnetSr2(Cu1−xPdx

Abstract

We investigate the Néel temperature of Sr 2 CuO 3 as a function of the site dilution at the Cu ͑S =1/2͒ sites with Pd ͑S =0͒, utilizing the muon spin relaxation ͑SR͒ technique. The Néel temperature, which is T N = 5.4 K for the undoped system, becomes significantly reduced for less than one percent of doping Pd, giving a support for the previous proposal for the good one-dimensionality. The Pd concentration dependence of the Néel temperature is compared with a recent theoretical study [S. Eggert, I. Affleck, and M. D. P. Horton, Phys. Rev. Lett. 89, 47 202 (2002)] of weakly coupled one-dimensional antiferromagnetic chains of S =1/2 spins, and a quantitative agreement is found. The inhomogeneity of the ordered moment sizes is characterized by the SR time spectra. We propose a model that the ordered moment size recovers away from the dopant S = 0 sites with a recovery length of Ϸ 150− 200 sites. The origin of the finite recovery length for the gapless S =1/2 antiferromagnetic chain is compared to the estimate based on the effective staggered magnetic field from the neighboring chains.

Evidence for Ballistic Thermal Conduction in the One-DimensionalS=1/2 Heisenberg Antiferromagnetic Spin System Sr2CuO3

“…28 The value of x Curie is found to be about a half of the Pd concentration, x. This is reasonably explained as follows.…”

“…These behaviors of χ are similar to those reported in the literature. 17,18,28 The experimental data of χ are well fitted using the following equation as in the former report: 18…”

Delocalization of the Cu2+Unpaired Electron on the Next Nearest Ligands in Sr2Pd0.99Cu0.01O3Ceramics

“…This study is a continuation of our earlier work in which we studied the crystals of the layer perovskite type [3]. In recent years the mixed Sr 2 Pd 1−x Cu x O 3 and Sr 2 Cu 1−x Ni x O 3 phases, being structural analogues of Sr 2 CuO 3 , have been studied by different methods [4][5][6][7]. Direct information about delocalization of the Cu 2+ unpaired electron on the nearest cations can be obtained from electron paramagnetic resonance spectra.…”

Magnetic ordering in the ultrapure site-diluted spin chain materialsSrCu1−xNixO2

“…24,25 One problem is that Zn 2+ , a traditional S = 0 substitute for Cu 2+ , does not readily enter the crystal structure during synthesis. 25 To date, only one focused study of long-range ordering in site-diluted Sr 2 CuO 3 has been reported. It was based on Pd 2+ substitution, but the exact concentration of defects was shown to be difficult to control, and no systematic studies for the concentration dependence of T N was performed.…”