The ancient Greeks and Chinese discovered that there is a natural magnetized stone in nature, which is called "the magnet." This stone magically sucks up small pieces of iron and always points in the same direction after a random swing. Early voyagers used this magnet as their earliest compass to discern the direction at sea. After thousands of years of development, today's magnets have become a powerful material in our lives. By synthesizing alloys of different materials, the same effect as that of the magnetite can be achieved, and the magnetic force can be increased. Man-made magnets appeared in the 18th century, but the process of making stronger magnetic materials was very slow until the 1920s when Alnico was made. Subsequently, ferrite was produced in the 1950s, and rare earth magnets were produced in the 1970s [Rare Earth magnets including NdFeB and SmCo). At this point, magnetic technology has developed rapidly, and magnetic materials have also made components more compact.
What is the magnetization (orientation) direction?
Most magnetic materials can be magnetized to saturation in the same direction, a direction called "magnetization direction" (orientation direction). A magnet that has no orientation direction (also called an isotropic magnet) is much weaker than an oriented magnet (also called an anisotropic magnet).