MAGNETIC-SUSCEPTIBILITY OF SOME MIXED-METAL COMPOUNDS - NBU(4)ZN(II)(X)FE(II)(1-X)[FE(III)(OX)(3)]

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 less than or equal to x<1 were studied in the temperature range of 5-290 K. The compounds with x less than or equal to 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.