Magnetic Materials : Properties, Working, Types, Differences & Their Applications

There are different types of materials & also substances that are made up of charged particles: like; electrons and protons. These materials can show some kind of magnetic properties when they are magnetized by an external magnetic field which is known as magnetic materials. These materials have induced or permanent magnetic moments in the magnetic field. To study these materials’ magnetic properties, usually, the material is located in a standardized magnetic field, then the magnetic field is changed. In modern technology, these materials play a key role and these are significant components for transformers, motors, and generators. This article provides brief information on magnetic materials.

What are Magnetic Materials?

The materials which are magnetized to an externally applied magnetic field are known as magnetic materials. These substances also obtain magnetization whenever they are attracted to the magnet. Examples of these materials are; Iron, Cobalt & Nickle.

These materials are categorized into magnetically hard (or) magnetically soft materials.

Magnetically hard materials are magnetized through a very strong external magnetic field which is generated by an electromagnet. These materials are mainly used for creating permanent magnets which are made from alloys usually consisting of changeable amounts of iron, nickel, aluminum, cobalt & rare earth elements like samarium, neodymium & dysprosium.

Magnetically soft materials are very easily magnetized although the induced magnetism is temporary. For instance, if you stroke a permanent magnet with a screwdriver or nail, then it will become magnetized temporarily & will generate its weak magnetic field because a large number of iron atoms are aligned temporarily in a similar direction through the external magnetic field.

Properties

Magnetic material properties are one of the most fundamental concepts of physics. So, the properties mainly include; paramagnetism, ferromagnetism, and antiferromagnetism which are discussed below.

Paramagnetism is a type of magnetism where some materials are attracted weakly by a magnetic field that is applied externally. It forms internal and induced magnetic fields within the applied magnetic field’s direction. In paramagnetism, the unpaired electrons are arranged randomly.

Ferromagnetism is a phenomenon where a material like iron becomes magnetized & remains magnetized within an external magnetic field for that stage. In ferromagnetism, the unpaired electrons are all connected.

Antiferromagnetism is a kind of magnetic order that mainly occurs whenever the adjacent atoms’ (or) ions’ magnetic moments align in reverse directions and results in zero net magnetic moments. So this behavior is mainly because of the exchange interaction between neighboring ions or atoms, which helps antiparallel alignment for reducing the energy of the system. Usually, Antiferromagnetic materials exhibit magnetic ordering under a specific temperature known as; Néel temperature. The material over this temperature will become paramagnetic and it loses its antiferromagnetic properties.

How Does Magnetic Materials Work?

These materials have small regions where the magnetic moment can be directed within a specific direction called magnetic domains which are responsible mainly for the exclusive performance of materials. The materials’ complete energy can be contributed simply by the anisotropy energy, exchange energy & magnetostatic energy. Whenever the magnetic material’s size is reduced, then it enhances various domains in the material. So due to the reduction within magneto-static energy, more domain walls will increase exchange & anisotropy energy. Thus, the size of the domain will decide the magnetic material’s nature.

The magnetic moment is not steady for some materials that have smaller particle diameters as compared to the critical superparamagnetism diameter. Whenever the diameter of the particle is between the critical diameter of superparamagnetism & single domain, then the magnetic moment will become stable.

Magnetic Materials Types

There are different types of magnetic materials available in the market which are discussed below.

Paramagnetic Materials

These materials are not attracted strongly to a magnet like; tin magnesium, aluminum, and many more. These materials have small relative permeability but positive like aluminum permeability of is: 1.00000065. These materials are only magnetized whenever they are located on a very strong magnetic field & they perform in the magnetic field direction.

Whenever a strong magnetic field is provided externally, then permanent magnetic dipoles adjust them into self-parallel for the applied magnetic field & increase to a positive magnetization. If the dipole orientation is parallel to the magnetic field applied is not complete, then the magnetization is extremely small.

Diamagnetic Materials

These materials are repelled through a magnet like mercury, zinc, lead, wood, copper, silver, sulfur, bismuth, etc are called diamagnetic materials. These materials have slightly below one permeability. For instance, the permeability of copper material is 0.000005, bismuth material is 0.00083 & wood material is 0.9999995.

When these materials are located in an extremely strong magnetic field, then these materials will be slightly magnetized & act in the opposite direction to the applied magnetic field. In these types of materials, there are two quite weak magnetic fields caused because of the orbital revolution & electrons’ axial rotation around the nucleus.

Ferromagnetic Materials

These types of materials that are attracted strongly through a magnetic field are called ferromagnetic materials. Examples of these materials are; nickel, iron, cobalt, steel, etc. These materials have extremely high permeability which ranges from several hundred to thousand.

The magnetic dipoles within these materials are simply arranged into different domains wherever the individual dipole arrangement is perfect significantly and that can generate strong magnetic fields. Usually, these domains are arranged randomly & every domain’s magnetic field is canceled through another and the whole material does not show the behavior of a magnet.

Whenever an external magnetic field is provided to these materials, then domains will reorient themselves to support the external field & generate a very strong internal magnetic field. By deduction of the external field, most of the domains wait & continue to be allied in the magnetic field direction.
Therefore, these materials’ magnetic field persists even whenever the external field departs. So this main property is used for producing Permanent magnets that we utilize daily. The materials used in making permanent magnets are usually highly ferromagnetic like Iron, nickel, neodymium, cobalt, etc.

Please refer to this link for Ferromagnetic Materials.

Magnetic Raw Materials

Usually, permanent magnets around the world are made with different types of materials and each material has different characteristics. These materials mainly include; alnico, flexible rubber, ferrite, samarium cobalt & neodymium which are discussed below.

Ferrites

The special group of ferromagnetic materials which occupy a middle position between ferromagnetic & non-ferromagnetic materials is known as ferrites. These materials have fine ferromagnetic material particles that possess high permeability & are held mutually through a binding resin. In ferrites, the magnetization generated is very sufficient although their magnetic saturation is not high like ferromagnetic materials.

These materials are not expensive to generate which is related to their magnetic strength. These are significantly weaker as compared to rare earth materials but even they are widely used still in several commercial applications. These materials have strength like resistance to corrosion & demagnetization.

Neodymium

Neodymium is a very rare earth element ((Nd) and its atomic number is 60 It was simply discovered in the year 1885 by Austrian chemist namely; Carl Auer von Welsbach. This material is mixed through boron, iron, and also traces of other elements like; praseodymium & dysprosium to generate a ferromagnetic alloy called Nd2Fe14b which is very strongest magnetic material. Neodymium magnets replace other kinds of materials in several industrial & modern commercial appliances.

Alnico

The acronym of aluminum, nickel & cobalt is ‘alnico’ where these three main elements are used mostly in creating alnico magnetic material. These magnets are very strong permanent magnets as compared to rare earth magnets. The alnico magnets can be replaced with permanent magnets within motors, loudspeakers & generators.

Samarium Cobalt

These magnets were simply developed by the U.S. Air Force Materials Laboratory in the early 1970s. Samarium cobalt or SmCo is a magnetic material that is made with an alloy of unusual earth elements like; samarium, hard metal cobalt, iron traces, hafnium, copper, praseodymium & zirconium. Samarium cobalt magnets are rare earth magnets like neodymium because samarium is an element of a similar rare earth group element like neodymium.

Magnetic Materials Vs Non-Magnetic Materials

The differences between these two materials are discussed below.

Comparison

The comparison between different magnetic materials is discussed below.

Applications

The applications of magnetic materials include the following.

• These are used to create and distribute electricity in the appliances that utilize electricity.
• They are utilized for data storage on audio, videotape & computer disks.
• These materials are used widely in life, production, national defense science & technology.
• These are used in the manufacturing of different transformers & motors within power technology, different magnetic components & microwave tubes within electronic technology, intensifiers & filters within communication technology, electromagnetic guns, household appliances & magnetic mines within national defense technology.
• These are used widely in mineral & geological exploration, ocean exploration & new technologies within energy, information, space & biology.
• These materials play a significant role in the electronic technology field & other science & technology fields.
• These are applicable in electronics, medicine, electrical engineering, etc.
• These are used in the manufacture of electronic & electrical devices like electric motors, transformers & generators.
• These are used in magnetic storage devices production like; floppy disks, hard disk drives & magnetic tape.
• These types of materials are used in magnetic sensor production like; Hall effect sensors, magnetic field sensors & magnetoresistive sensors.
• These are applicable in medical equipment like; MRI machines, pacemakers & implantable drug delivery systems.
• These are utilized in magnetic separation methods, which are utilized to disconnect magnetic particles from non-magnetic particles.
• These materials are used in the generation of renewable energy like; hydroelectric power plants & wind turbines.

Thus, this is an overview of magnetic materials, types, differences, materials comparison, and its applications. Here is a question for you, what is a magnet?