Theoretical Analysis of the Reduction of Neel Temperature in La$_{2}$(Cu$_{1-x}$Zn(or Mg)$_x)$O$_{4}$

T. Edagawa; Y. Fukumoto; A. Oguchi

doi:10.1016/j.jmmm.2006.10.386

paper

Theoretical Analysis of the Reduction of Neel Temperature in La $_{2}$ (Cu $_{1 - x}$ Zn(or Mg) $_{x})$ O $_{4}$

arXiv:cond-mat/0610005 · doi:10.1016/j.jmmm.2006.10.386

Abstract

Using Tyablikov's decoupling approximation, we calculate the initial suppression rate of the Neel temperature, $R_{I S} = - l i m_{x - > 0} T_{N}^{- 1} d T_{N} / d x$ , in a quasi two-dimensional diluted Heisenberg antiferromagnet with nonmagnetic impurities of concentration $x$ . In order to explain an experimental fact that $R_{I S}^{(Z n)} = 3.4$ of the Zn-substitution is different from $R_{I S}^{(M g)} = 3.0$ of the Mg-substitution, we propose a model in which impurity substitution reduces the intra-plane exchange couplings surrounding impurities, as well as dilution of spin systems. The decrease of 12% in exchange coupling constants by Zn substitution and decrease of 6% by Mg substitution explain those two experimental results, when an appropriate value of the interplane coupling is used.

2 pages, 3 figures

Theoretical Analysis of the Reduction of Neel Temperature in La2​(Cu1−x​Zn(or Mg)x​)O4​

Abstract

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Theoretical Analysis of the Reduction of Neel Temperature in La $_{2}$ (Cu $_{1 - x}$ Zn(or Mg) $_{x})$ O $_{4}$