Weak ferromagnetism in a diamagnetically diluted sublattice of Fe3+ ions in solid solutions Y2 −x Fe1 +xTaO7 (x = 0 –0.2) with pyrochlore-like structure

Abstract

A series of layered solid solutions Y2-xFe1+xTaO7 (x = 0–0.2) was synthesized and a structural transition (space group R3¯ ↔ space group P3121) was observed at x = 0.1. In Y2−xFe1+xTaO7, which belongs to both structural types, geometrically frustrated 2D sublattices of kagome-type are formed, in which Fe3+ ions are coupled by short-range antiferromagnetic interactions, and the transition to the spin glass state is observed at Tg ∼ 4.3 K. A phenomenon of weak ferromagnetism has been detected, the cause of which is probably a small tilt of the Fe3+ spins due to the Dzyaloshinskii–Moriya antisymmetric superexchange.