The rotational magnetism of magnetic materials refers to the phenomenon where a plane polarized electromagnetic wave * propagates in a certain direction within the material under the action of two mutually perpendicular DC magnetic fields and electromagnetic wave magnetic fields, and its polarization plane * * continuously rotates around the propagation direction (Figure 3). This type of material with rotational magnetic properties is called a rotational magnetic material.

Under the action of direct current magnetic field and electromagnetic wave magnetic field, the phenomenon where a plane polarized electromagnetic wave * propagates in a certain direction within the material, and its polarization plane * * continuously rotates around the propagation direction. This material with rotational magnetic properties is called a rotational magnetic material. Although metal magnetic H material also has rotational magnetism, due to its low resistivity and high eddy current loss, electromagnetic waves cannot penetrate into the interior and can only enter the skin with a thickness of less than 1 micrometer (also known as skin effect), making it unusable. Therefore, the application of spin magnetism in magnetic materials has become a unique field for ferrite.

The spin magnetic phenomenon is actually applied in the band of 100-100000 MHz (or in the range of meter to millimeter waves), so ferrite spin magnetic materials are also known as microwave ferrite. Commonly used microwave ferrites include magnesium manganese ferrite Mg MnFe2O4, nickel copper ferrite Ni CuFe2O4, nickel zinc ferrite Ni ZnFe2O4, and yttrium garnet ferrite 3Me2O3 · 5Fe2O3 (Me is a trivalent rare earth metal ion, such as Y3+, Sm3+, Gd3+, Dy3+, etc.)

Rotating magnetic materials are mostly composed of various microwave devices, such as waveguides or transmission lines, which transport microwaves. They are mainly used in electronic devices such as radar, communication, navigation, telemetry, and remote control. Microwave devices are mainly used in electronic devices such as radar, communication, navigation, telemetry, and remote control.