Weak ferromagnetism in a diamagnetically diluted sublattice of $\mathrm{Fe^{3+}}$ ions in solid solutions $\mathrm{Y_{2-x}Fe_{1+x}TaO_7}$ ($x = 0\text{-}0.2$) with pyrochlore-like structure

A series of layered solid solutions $\mathrm{Y_{2-x}Fe_{1+x}TaO_7}$ ($x = 0\text{-}0.2$) was synthesized and a structural transition (space group $R\overline{3}$ $\leftrightarrow$ space group $P3_{1}21$) was observed at $x=0.1$. In $\mathrm{Y_{2-x}Fe_{1+x}TaO_7}$, which belongs to both structural types, geometrically frustrated 2D sublattices of kagome-type are formed, in which $\mathrm{Fe^{3+}}$ ions are coupled by short-range antiferromagnetic interactions, and the transition to the spin glass state is observed at $T_g \sim 4.3 K$. A phenomenon of weak ferromagnetism has been detected, the cause of which is probably a small tilt of the $\mathrm{Fe^{3+}}$ spins due to the Dzyaloshinskii–Moriya antisymmetric superexchange.