The Lightest Magnet Invented?

Almost all electronics have magnets. Cell phones, televisions, computers, even cars contain magnets. The introduction of lighter weight magnets could mean making electronics lighter weight, more efficient, and maybe less expensive.

A group of scientists in the Centre de Recherche Paul Pascal discovered a new way to design magnets. The properties of the magnets make them promising updates to replace or complement traditional inorganic magnets.

Current Demand for Traditional Manets

There is a great demand for new magnetic materials. This is a result of many magnets being made from metallic elements or rare earth metals. These types of magnets, ferromagnets can be used at room temperature; which is the working temperature for most applications. In 2019 the global market for inorganic magnets totaled 19.5 billion dollars and it is expected to reach almost 30 billion dollars by 2025.

Inorganic magnets can be expensive to make and access to the raw materials to manufacture them is limited. This makes the manufacturing cost of magnets relatively high. Due to the expense to manufacture and the limitations in raw material availability material scientists have been working diligently to find inexpensive ways to manufacture magnets. They are investigating more cost-effective materials and manufacturing processes. with more readily available materials. To date, there have not been many materials developed that can operate at room temperature and are inexpensive to manufacture.

Development of the Light Weight Magnet

Lead research was Rodolphe Clerac at the University of Bordeaux CNRS is the research facility. New chemical strategy to design magnets based on the coordination networks composed of an inorganic radical. Inorganic radicals are atoms, molecules, or ions that have an unpaired valence electron. In skincare, radicals can be a source of damage and aging. However, in this application radicals are being leveraged to create magnets from new materials.

The group of researchers looked to leverage organic radicals that have an unpaired electron and a paramagnetic metal ion to create a polymer that has a very strong magnetic interaction. If you remember from the article about magnetic materials, a paramagnetic magnet is a material that is weakly attracted when an external magnetic field is applied. On the atomic level, the electrons behave like little tiny magnets. When the external magnetic field is applied the electrons’ spins to align parallel to the field, causing a net attraction

The coordination network or polymer that the team created had operating temperatures up to 242 C and large coercivity. Coercivity is a magnet’s ability to withstand a large external magnetic field without becoming demagnetized. Probably the most unique property of the magnet is that it has a low density.

The Density of Traditional Magnets

Density is a measurement of a material’s mass per unit volume and it varies depending on the materials. For example, if we have two materials and a scale that has a 5 lb weight on it. It will take a lot more of the lower density material to balance out the scale compared to a high density material. Specifically for magnets, traditional magnets are pretty dense.

For example, neodymium is a common rare earth metal used to make magnets. This one of the most common materials for magnets you can find at local home improvement stores and hardware shops. The density of neodymium magnets is about 7.5 g/cm3. Comparatively the new lightweight magnet that was developed has a density of 1.2g/cm3. That means this new magnet is more than 6 times lighter than a traditional magnet. Let me know down in the comments what you think some cool uses for these lightweight magnets would be.

Synthesizing Lightwieght Magnets

And not only are these magnets significantly lighter weight but they are also relatively easy. Especially when compared to other methods for magnets that are not made from the traditional rare earth metals. The process is termed a post-synthetic reduction of preassembled coordination networks that incorporate chromium metal ions and pyrazine building blocks.

This synthesis method means the scientist synthesizes a polymer that contains chromium ions, an inorganic metal ion and binds it with pyrazine, an organic compound. These two molecules combined to form a polymer that is sometimes called an organometallic polymer, coordination polymer, or coordination network and then they perform a chemical reaction on it called reduction. During the reduction reaction, the coordination polymer gains electrons and develops that paramagnetic behavior that we talked about earlier. This process is already widely used for fuel cells and electronic applications. However, the translation of this method to magnetic materials makes it a cool and exciting new application and opens up new possibilities.

Limitations of the Lightweight Magnets

So while these magnets show a lot of promise some of the current limitations as that they are air-sensitive and have poor crystallinity which means the applications of the magnets are currently limited and they are not as efficient. As the group of researchers works to improve their innovation it will be exciting to see how these lighter weight magnets are implemented.