Magnetic studies on a new low-dimensional antiferromagnetic iron phosphate

Abstract

A quasi-one-dimensional three-legged iron phosphate ladder, containing iron atoms connected through F bridges, giving rise to a three-legged Fe core, which are linked through P atoms, has been synthesized. Magnetic susceptibility data show the characteristics of Curie behavior at low temperature, which is attributed to an impurity concentration of 0.46% made free by lattice imperfections. The magnetic susceptibility attains saturation far below room temperature, possibly due to very weak superexchange interactions along the chains. The observed room temperature magnetic moment corresponds to the spin-only moment of Fe³⁺ with S = 5/2 and passes through a minimum of 4.16 μ_B per Fe at 40 K, before increasing again as T → 0. The magnetization as a function of the magnetic field shows complete polarization of the magnetic ions around 5 T at low temperature.