Different ratios of Fe(acac)3/Mn(acac)2 precursor (Fe/Mn ratio) were employed to tune the MnxFe3-xO4 composition from x = 0.14 to 1.4 through one-step thermal decomposition method . The reagents amount used for all samples is shown in Table in the S.I. Briefly, 15 mmol of the mixture of metallic precursors at different Fe/Mn ratios were dissolved in 150 mL of benzyl ether (BE) to obtain x = 0.14, 0.20, and 0.37 MNPs (large-scale synthesis, A Series), while 5 mmol of the metallic precursors, but maintaining the same Fe/Mn ratios were dissolved in 50 mL of BE to obtain the MNPs with x = 0.40, 0.70 and 1.4 (small-scale synthesis, B Series). For the small-scale synthesis, 10 mmol of 1,2-hexadecanediol (HDD) were used, whereas in large scale synthesis, 30 mmol were employed.