• DOI:10.1103/PhysRevB.96.094438
• Corpus ID: 119443726

Absence of magnetic long range order in Y2CrSbO7: bond-disorder induced magnetic frustration in a ferromagnetic pyrochlore

@article{Shen2017AbsenceOM,
  title={Absence of magnetic long range order in Y2CrSbO7: bond-disorder induced magnetic frustration in a ferromagnetic pyrochlore},
  author={L. Shen and Colin Greaves and R. Riyat and Thomas Christian Hansen and Elizabeth Blackburn},
  journal={Physical Review B},
  year={2017},
  volume={96},
  pages={094438}
}

• L. Shen, C. Greaves, +2 authors E. Blackburn
• Published 6 March 2017
• Materials Science
• Physical Review B

The consequences of nonmagnetic-ion dilution for the pyrochlore family Y$_{2}$($M_{1-x}N_{x}$)$_{2}$O$_{7}$ ($M$ = magnetic ion, $N$ = nonmagnetic ion) have been investigated. As a first step, we experimentally examine the magnetic properties of Y$_{2}$CrSbO$_{7}$ ($x$ = 0.5), in which the magnetic sites (Cr$^{3+}$) are percolative. Although the effective Cr-Cr spin exchange is ferromagnetic, as evidenced by a positive Curie-Weiss temperature, $\Theta_\mathrm{{CW}}$ = 20.1(6) K, our high-resolution neutron powder diffraction measurements detect no sign of magnetic long range order down to 2 K. In order to understand our observations, we performed numerical simulations to study the bond-disorder introduced by the ionic size mismatch between $M$ and $N$. Based on these simulations, bond-disorder ($x_{b}$ $\simeq$ 0.23) percolates well ahead of site-disorder ($x_{s}$ $\simeq$ 0.61). This model successfully reproduces the critical region (0.2 < $x$ < 0.25) for the N\'eel to spin glass phase transition in Zn(Cr$_{1-x}$Ga$_{x}$)$_{2}$O$_{4}$, where the Cr/Ga-sublattice forms the same corner-sharing tetrahedral network as the $M/N$-sublattice in Y$_{2}$($M_{1-x}N_{x}$)$_{2}$O$_{7}$, and the rapid drop in magnetically ordered moment in the N\'eel phase [Lee $et$ $al$, Phys. Rev. B 77, 014405 (2008)]. Our study stresses the nonnegligible role of bond-disorder on magnetic frustration, even in ferromagnets.