Fig. 3

Magnetometry measurements. a Susceptibility versus temperature for five samples of CaFe₃O₅ measured in 1000 Oe fields. The transition at the marked T_N is a property of the main phase, while the absolute values of the susceptibility and transitions at lower temperatures in some samples appear to be strongly influenced by minuscule quantities of more strongly magnetic impurities such as Fe₃O₄ and Ca₂Fe₂O₅ b Magnetisation Isotherm of sample E at 5 K, showing a low moment and no hysteresis, consistent with antiferromagnetic behaviour. c and d real and imaginary parts of the AC susceptibility of sample A which show no ferromagnetic component to the transition at T_N.