I am creating a product that incorporates magnetic sensing of magnetic nanoparticles. However due to their cost, I have decided to search for other avenues of testing. My question is about whether Iron Powder will retain a magnetic field once magnetized. I basically will place some iron powder in a small container above the sensor, and apply a uniform magnetic field perpendicular to the sensitive axis of the magnetic sensor (the magnetic sensor will not sense the applied magnetic field). Once I turn the field off, will the powder retain the magnetic orientation and produce its own magnetic field? I theorize that it will due to iron powder being ferromagnetic, but am not sure, so any clarification would be appreciated. Thanks!!