A magnetic fluid composition include a suspension of nano-particles including cross-crystallized multi-metal compounds dispersed in a solvent, the cross-crystallized multi-metal compounds including at least two or more metals having different valencies or oxidation states, the metals selected from the group consisting of a monovalent metal (Me+), a divalent metal (Me2+), a trivalent metal (Me3+), a quadrivalent metal (Me4+) and a rare earth metal. The magnetic fluid having a viscosity and surface tension that permits dispensing from an inkjet printer at a rate of at least 2.5 m/s, at a resolution of at least 600 dpi, supporting jetting pulse frequencies of at least 15 KHz per nozzle (enabling high speed inkjet printing applications of at least 0.6 m/sec per individual nozzle row per print head), and enabling uninterrupted, industrial level print output of magnetic ink character recognition (MICR) code lines suitable for high speed magnetic data scanning per established industry regulations (ANSI X9).