Microscopic coexistence of antiferromagnetic and spin-glass states

Abstract

The disordered antiferromagnet PbFe${}_{1/2}$Nb${}_{1/2}$O${}_{3}$ is investigated in a wide temperature range by combining M\"ossbauer spectroscopy and neutron diffraction experiments. It is demonstrated that the magnetic ground state is a microscopic coexistence of antiferromagnetic and spin-glass orders. This speromagnetlike phase features frozen-in short-range fluctuations of the Fe${}^{3+}$ magnetic moments that are transverse to the long-range ordered antiferromagnetic spin component.