The effect of aluminum on magnetic barrier is not obvious. Why?
The electron spin and the orbital angular momentum leads to a dipole moment and the formation of a magnetic field. In most material in the total magnetic moment is zero. All the electronic dipole layer only electronic atoms (dissatisfaction unpaired electrons) may represent a net magnetic moment in the absence of external magnetic field under the condition of ferromagnetic materials have many. This electronic. If they are arranged together so they can together produce a can be observed by macroscopic field.These dipoles tend to point to the direction of the external magnetic field. This phenomenon is called paramagnetic. The dipole of a ferromagnetic material tends to point in the same direction without an external magnetic field. This is a quantum mechanical phenomenon
According to the characteristics of Km, the testing materials can be divided into 3 categoriesThe anti magnetic material (Diamagnetic Material)The relative permeability of the diamagnetic material Km is less than 1, but approximately equal to 1., for example, Km=0.9999906 of copper, Km=0.9999831. of leadFor diamagnetic materials, if the external magnetic field is removed, the internal magnetic field will be zero, resulting in no magnetismThe paramagnetic material (Paramagnetic Material)The Km of paramagnetic material is greater than 1, but approximately equal to 1, only a little larger than 1. If the external magnetic field is removed, the internal magnetic field will be zero, resulting in no magnetism, such as aluminum Km=1.0000214The ferromagnetic material (Ferromagnetic) Material)The ferromagnetic material Km is much larger than the 1. If the external magnetic field is removed, the internal magnetic field will not be zero, and its magnetic force will be preserved. Generally, iron, cobalt and nickel are ferromagnetic, and their relative permeability is Km more than 1000
Ferromagnetism refers to the magnetic state of a material and has a spontaneous magnetization phenomenon. The most widely known material in the material is iron, hence its nameA test substance is placed in a solenoid in which B0 is the magnetic field without testing the material in the solenoid. Bm is the magnetic field in the solenoid when it is filled with test material
