Hard ferrites are a type of magnetic material made primarily from iron oxide combined with other metal oxides, such as barium or strontium. They are known for their high magnetic strength and resistance to demagnetization, making them ideal for permanent magnets used in various applications, including speakers and electric motors. These materials are produced through a process called ceramic sintering, which involves heating the raw materials to high temperatures. Hard ferrites are cost-effective and widely used in industries due to their stability and durability, contributing to their popularity in the manufacturing of magnetic components.