fireace

I have been trying to make a ferrofluid with magnetite of size around 1um, the results, not quite fluid alike. It is the commercial available powder magnetite of ~1um, i used about 1 spatula of powder, 20ml of baby oil(serves as carrier), 2ml of oleic acid(serves as surfactant), i put them on a hot plate magnetic stirrer, heat it up while stirring(without using magnetic stir bar as i can see the solution flowing because of the strong magnetic response of magnetite). after around 15 minutes i have a look on the solution, it seems quite similar to the ferrofluid seen online. i place a magnet near it, spikes are forming, but the sad part is that, it separates into two forms, ie. the wet magnetite and transparent liquid solution(of baby oil and oleic acid), i can safely decant away the liquid without losing any of the magnetite after the removal of magnet, the wet magnetite will not remains back to the fluid form as the carrier liquid is already separated from it i took some photos after decanting the extra liquid, without magnetic field with magnetic field after magnet has been removed the wet magnetic, without the presence of carrier liquid, can't even gets back into relaxed shape i have been trying with various combination of carrier medium including acetone, kerosene, with coating of oleic acid, without coating, volume of carrier, volume of surfactant, i even tried synthesizing a nano sized magnetite and tried with same steps to prepare the ferrofluid, all attempts are in vain so here comes the question, how should i prepare a real ferrofluid, with the materials i have, namely ~1um size magnetite powder and also nano scaled synthesized magnetite? did i make any mistakes on preparing it, or perhaps i am missing any secret little steps? thanks for the help!