Gigantic Impact of Magnetic Impurity on Stripe Order in La$_{2-x}$Sr$_{x}$CuO$_4$ ($x$$\sim$1/8)

TL;DR

This study reveals that magnetic and non-magnetic impurities in La$_{2-x}$Sr$_{x}$CuO$_4$ can stabilize static stripe order, with magnetic impurities like Fe significantly enhancing charge and spin-density waves, highlighting impurity effects on stripe stability.

Contribution

First demonstration that impurity substitution stabilizes static stripe order in La$_{2-x}$Sr$_{x}$CuO$_4$ across different crystal structures, emphasizing magnetic impurity effects.

Findings

Fe substitution enhances charge- and spin-density-wave orders.

Static stripe order appears in the low-temperature-orthorhombic phase due to impurities.

Magnetic moments at Cu-sites suppress spin fluctuations, promoting static charge order.

Abstract

Precise neutron-scattering experiments on La$_{1.88-y}$Sr$_{0.12+y}$Cu$_{0.99}$R$_{0.01}$O$_4$ ($y$=0 for R=Cu, Zn and $y$=0.01 for R=Ga, Fe) were performed to examine the stability of stripe order in cuprate oxides through impurity substitution effects. For all the impurity-substituted samples a static charge-density-wave order similar to that reported in the low-temperature-tetragonal phase (LTT) was discovered in the low-temperature-orthorhombic (LTO) phase for the first time. Fe substitution significantly enhanced both the charge- and spin-density-wave orders. These results indicate that dynamical charge stripes can be stabilized into static ones around the Cu-site defects regardless of the type of crystal structure. Additionally, large magnetic moments at the Cu-site may induce a decrease in the Cu spin fluctuations around the defects, which in turn, enhances the static charge-density-wave order.