Magnetic investigations on six compounds with the general formula (Ca,Y)Ba(Co,Fe,Al,Zn)4O7 and the structures of YBaCoFeZn2O7 and YBaCo2FeZnO7

YBaCoFeZn2O7 and YBaCo2FeZnO7 are isostructural (YBaCo4O7 type, P63mc, a=6.3, c=10.3Å). Four of the compounds, CaBaCo2FeZnO7, CaBaFe2Zn2O7, YBaCoFeZn2O7, and YBaCo2FeZnO7, exhibit magnetic transitions in the range 6-65 K. There are indications of transitions for YBaFeZn3O7 and CaBaFeZn2AlO7, but these must be below 3 K.The AC magnetic susceptibilities (χ) are frequency dependent: higher frequency increases the transition temperature. A loss in the magnetic energy is seen as peaks in the imaginary part of χ on the low temperature side of the real-part transition. The changes in Tf with frequency, for both real and imaginary part of χ, are modelled using Arrhenius-, Vogel-Fulcher-, and power-law-calculations. The modelling indicates that the compounds are similar to metallic spin-glasses.Magnetisation up to 8 T did not magnetically saturate any of the samples. CaBaCo2FeZnO7 and CaBaFe2Zn2O7 exhibit no clear difference between zero-field cooled (ZFC) and field-cooled (FC) magnetisation as well as no thermoremanent magnetisation (TRM) in the relaxation measurements, suggesting that these two compounds are more similar to disordered anti-ferromagnets. For YBaCoFeZn2O7 and YBaCo2FeZnO7, ZFC data have lower magnetisation than FC data and TRM is present, although full relaxation is reached within 102-103 seconds; these could be disordered anti-ferromagnets with spin-glass features.Double-exchange (DE) between Co2+ and Co3+ is the suggested mechanism responsible for the notable difference in properties between CaBaCo2FeZnO7 and YBaCo2FeZnO7, where the former has a significant DE and the latter not.