Magnetic materials are objects that alter the value of the magnetic field in which they are situated. They are materials that are attracted by a magnet. Electrons of a material are affected by magnetic forces when a magnetic field is placed near it through a law known as faraday’s law of induction. The reaction of magnetic materials in the presence of external magnetic field depends on several factors; they include: the molecular and atomic structure of the object and the net magnetic field of the atoms. The magnetic moments involved in the atoms originates from; the spin of electrons, change in movement caused by the magnetic field and electron movement. Electrons always occur in pairs in several atoms i.e. negative and positive which causes their magnetic field to cancel each other. Examples of magnetic materials include steel, cobalt, nickel and iron.
Ferromagnetic materials are affected by the external magnetic field. These materials retain their magnetic properties after the magnetic field is removed. This is because they contain magnetic domains that are arranged parallel hence their magnetic force is strong within the domains. Once the magnetic field is taken away, the domains become randomly arranged hence the net magnetic for the whole part is zero. When the domains are magnetized becomes arranged hence producing a strong magnetic field. Paramagnetic materials have a positive and small effect to the magnetic field. They are magnetic materials that are not strongly attracted by a magnet, and they do not retain magnetic material after the magnetic field is removed. This is because they contain unpaired electrons, and the domains are not arranged parallel due to external magnetic field. Diamagnetic materials have a negative and weak effect to the magnetic fields. They are materials that are slightly repelled by a magnet. This is because they contain electrons that are paired hence there is no net magnetic moment per atom. After the magnetic field is removed diamagnetic materials does not retain magnetic properties. They include copper, gold and silver.
Magnetic materials are used for cooling Microsystems that are based on thermo magnetic convection. The magnetic material acts as a coolant where the magnet is the pumps drawing the magnetic material to the part that needs to cool. Magnetic materials are applied in medicine by transporting medications to the required stations within the body of a human being. Magnetic materials can be used in sealing liquids in the device. For example Ferro liquid can be required to cover the rotating shaft in computer hard disk.