Magnetic Susceptibility of Some Mixed-Metal Compounds: NBu₄Zn(II)_xFe(II)_1-x[Fe(III)(ox)₃]

Abstract

The temperature dependence of the molar magnetic susceptibility of NBu 4 Zn(II) x Fe(II) 1- x [Fe(III)(ox) 3 ] compounds, where NBu 4 + =tetra-n-butylammonium ion and ox 2- =oxalate ion with 0≤ x <1 were studied in the temperature range of 5-290 K. The compounds with x ≤0.1 showed two susceptibility maxima on temperature scale in 40.5-43.5 K and 10-24 K temperature ranges. These compounds undergo ferrimagnetic transition in the 40.5-43.5 K range. The difference in their magnetic susceptibility variations with temperature in the field-cooled and zero field-cooled modes indicated that these compounds exist in a “spin-glass” like state below 35 K range. The molar magnetic susceptibility variation with temperature obeys the Curie-Weiss law at higher temperatures ( >90±10 K). Several x dependent Curie-Weiss constant were evaluated.