Coercivity and the Horseshoe

Magnets have been in use for ages and currently the shape that is most recognized and is used to represent magnets is the horseshoe. Why is it that magnet are usually made in this shape and why does it provide an advantage over the other shapes?

Many people say that magnets are designed like horseshoes because putting two poles together brings about much greater force and this increases the strength of the magnet’s hold. This is true but it may not be the only reason. You can still be able to put two poles together if you place two magnets side by side. Think about the horseshoe and specifically the circular part. This part does not get used and may be viewed as extra material. This therefore disqualifies this theory as being the only reason for the horseshoe shape being used in magnets.

Coercivity

A magnet is usually considered strong depending on the pull force experienced when it is in use. A magnet’s strength can also be measured by finding out the magnetic field strength that will be able to demagnetize it. This is what is known as coercivity.

 Earlier magnets had such a low coercivity that their own magnetic fields were able to demagnetize them. These magnets were mostly made of iron. More powerful magnets have been developed over time and this includes an increase in coercivity as well. Neodymium magnets are stronger than most magnets and they also have a higher coercivity and this allows them to maintain their magnetism over time.

Significance of the horseshoe shape

The shape of a magnet influences how much magnetization is lost. A long cylindrical magnet will stay magnetized longer compared to a thin disc magnet. It takes a little more to demagnetize a horseshoe because it is like a stretched version of a cylindrical magnet.

The permeance coefficient (Pc) of a magnet is defined as how difficult it is for a magnet’s field lines to move from the north pole to the South Pole. This means that taller magnets will have a higher Pc and shorter magnets a lower Pc. A horseshoe has a high Pc as well. This prevents it from easily getting demagnetized. This is further increased by using a steel keeper.

This explains why neodymium magnets are not made into the horseshoe shape. Neodymium is a very strong magnet that does not demagnetize at all. In the event that a neodymium magnet gets demagnetized, you will find that the magnet was probably very thin or it was exposed to very high temperatures.

You can even place two neodymium magnets together without causing them to demagnetize each other. Their coercivity is very high which makes them more flexible for use in different applications. Neodymium is also a hard and brittle material. Shaping it into horseshoes would cause them to break very easily.

This shape is therefore applied to magnets with low coercivity like Alnico and iron. They will be able to keep their magnetization for longer with this shape.

For more information about various magnets, please visit http://www.samaterials.com/214-neodymium-magnets.

Significance of A Disc Magnet

The hard drive is like the brain of the computer. It is responsible for storing all the data and information. Disc magnets work well in storing the data in the hard drive of a computer. Through the use of Disc magnets you can easily write to the drive, store data and can very well read the data on the hard drive. The transfer and erase of data using Disc magnets is very easy. Storing and retrieval of data through a magnetic mechanism is more simple and reliable. It can store data for over the years without any damage. While in case if for any reason the hard drive no longer works, even then you can able to recover your stored data through removing the magnet from the hard drive. The hard drive stores all the information in it and can retrieve whenever needed.

If you get into the mechanism of a hard drive, you will find it is just made up of a several different parts; those are electrical board, the plotter and a head. The disc magnet gets regulated by this electrical board. The plotters are responsible to store information. These are the aluminium or glass discs coated with a magnetized material to store and record data. It has been seen a few computers use more than one plotter as it can store huge data in less space.

While if for any good reason the hard drive stop working and fails to store and retrieve data from its memory, you can easily remove the magnet from the non working dead drive. You can able to get back your stored information through the help of the magnet, even when the hard drive doesn’t work. The plotter is attached to the magnets through screws and would be removed while removing the magnets. The magnets fixed with glue to the hard drive. When a a hard drive fails to work, the magnets are removed from the device. But if the hard drive is once opened, it cannot be used again. But the better part is that the data stored in the magnets of the hard drive can be recovered.

Many other electronics devices store information in the same way. If you will see the mechanism of video tapes and music cassette tapes you will find a great similarity in storing information. These magnets are not same like the disc magnets found on hard drives, but they are very powerful magnets and thus used in different significant purposes.

For more information about various magnets, please visit http://www.samaterials.com/213-rare-earth-magnets

A Discovery of the rare-earth element

It is the amazing magnetic field which exists behind almost every technological device used for the modern commercial, industrial as well as household purposes. The rare earth elements used in the advanced motors, generators and computers to minimize the use of electric power is nothing but the earth magnets. It possesses the magnetic field similar to the permanent magnets. That means it is almost impossible for these magnets to demagnetize. Only heat is the core enemy of the magnet. A neodymium can lose its magnetic power in elevated heat. In fact the magnets are so strong and powerful because of the raw metal used to make them tremendously powerful.

The earths magnets are made of the material called ferromagnetic metals, which, when magnetized can generate a strong magnetic pull. This magnetic pull or magnetic field is responsible for the attraction of the metal. It is so powerful that it can crush your finger if it comes between two magnets. Often it can become the reason of serious health complications if swallowed by little children. So it is advisable to keep it away from the reach of the kids. Though magnets are the metal of fun, but children should not be allowed to play with it. A few preventive cautions are there which should be followed to safeguard you from the hazard of the metal. While handling big strong magnets it is wise to cover your eyes and hands with proper protection. Neodymium is a brittle metal so while machining there is a chance of breaking of the magnet and the tiny particles of the metal can fly in airs which are not less sharp than glass particles. These magnets can even break if dropped from the hand.

In the later years of 1900, Earth magnets were discovered. Since that day researches are going on to produce more and more strong magnets. The permanent magnets can be used for scientific, commercial, industrial and household applications. the Neodymium magnets are safe and affordable. That is the reason it is widely used by school children in their various science experiments. It has a wide usage in household application also. In the scientific community it can be used in the mechanism of self-powered flashlights, computers, cordless devices, in different electronic devices, refrigerator, washing machine, microwave and the like. All the electromagnetic devices rely on magnets for their function. Starting from the hard drive of a computer to the magnetic credit card, all functions with the power of magnets.

For more information about various magnets, please visit http://www.usrareearthmagnet.com/

Types of Rare Earth Magnets

Magnets have been in existence for a very long time and magnet strength has increased as innovations and further research continues. A stronger magnetic material was developed in the 1900s and it has continued to be used in various industrial applications.

This material is composed of a combination of rare earth elements. Magnets derived from these materials are therefore known as rare earth magnets. They are the strongest magnets currently available, with their strength being significantly higher than all regular magnets. They may produce a magnetic field of about 1.4 teslas while other magnets produce about 0.5 to 1 tesla.

Rare earth metals are not really rare because their abundance may be similar to metals like lead or tin. These metals are naturally ferromagnetic. This means that they can be magnetized permanently but their natural magnetism is only visible below certain temperatures. When mixed with metals that possess magnetism at higher temperatures such as nickel, iron and cobalt they form quality compounds that make for good magnets.

Weak points

Their biggest weakness is that they are very brittle. They break very easily and can easily get corroded or chipped. They are therefore usually covered in a less brittle material like plastic to avoid constant damage from breakage or chipping.

Advantage

The atoms found in rare earth elements have been found to have a very high magnetic anisotropy. This refers to the ability of the particles to get easily magnetized in one direction but they resist magnetization in another direction.

Rare earth magnets are of two types, namely samarium-cobalt magnets and neodymium magnets. Of the two types, neodymium magnets are more common.

Samarium-cobalt (SmCo) magnets

These are the first type of rare earth magnets that were invented but they are not commonly used. This is due to the fact that they have a weaker magnetic strength and are more expensive. They are however used for applications that require a high magnetic field strength under high temperatures because their Curie temperature (the temperature at which it loses its magnetism) is higher.

Neodymium magnets

These are made of neodymium, iron and boron and may sometimes be referred to as NIB. They are the most affordable and strongest of rare earth magnets. Their application is mainly in devices that require strong permanent magnets for instance jewelry clasps, cordless tools and computer hard drives. They have to be coated to prevent corrosion.

 Ferrite magnets

These are made of compounds that are combinations of iron (III) oxide and ceramic materials. They are brittle, hard and normally non-conductive. There are hard and soft ferrite magnets.

AlNiCo

AlNiCo is actually an acronym that stands for aluminum, nickel and cobalt since these magnets are alloys of these three materials. You will sometimes find titanium and copper in them. They are highly resistant to losing magnetism, are ferromagnetic and are therefore used in the production of permanent magnets. They were actually the strongest magnets before rare earth magnets were developed in the 1970s. Their strength is only exceeded by rare earth magnets where more powerful magnets are required for industrial use.

For more information about various magnets, please visit http://www.usrareearthmagnet.com/