Rare earth magnets were not developed until the 1970’s. Researchers were looking for materials that would constitute the primary matter in newer, stronger magnets that they could use to increase industrial output and also use in the increasing number of electronic devices demanded by the world’s population. These materials, it was hoped, would possess stronger magnetic fields and resist demagnetization better than ferrite and alnico magnets, which were the most commonly used magnetic materials up through the middle of the 20th century.
The term ferro fluid refers to a liquid made of microscopic, ferromagnetic particles which acquires a powerful magnetism in the presence of another magnetic field. The particles are known as nanoparticles because of their extremely small size. These fluids are artificially produced in industrial settings. Each particle receives a coating of surfactant. This is a special compound that reduces surface tension and inhibits clumping among the ferromagnetic particles. The particles have a tendency to remain evenly spread throughout the fluid and resist settling. There are many types of applications for these fluids.