The secret of powerful magnets

In our daily life, the magnet is a very common thing. And thousands of years ago, the working people of our country made one of the four great inventions, the compass, according to the characteristics of the magnet. Magnets are very useful to this day. From a variety of special electronic equipment to the usual teaching toys, one can often see the figure of magnets. Pictured below is a horseshoe-shaped magnet with a lump of metal called gadolinium (GA). This is an element that, like iron, cobalt, and nickel, is attracted by magnets and is now widely used to enhance MAGNETIC resonance imaging.

We know that the main component of a magnet is ferric oxide. A small ordinary magnet is made of black iron oxide. But because of the nature of ferric oxide, its attraction to iron objects is not very strong, and its magnetism weakens over time. So how do you make a magnet that's stronger and less prone to decay? Under such a premise, the NdFeB magnet came into being.