Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Most Magnetic Metal, Material
Name: Steven
Status: other
Grade: other
Location: NV



Question:
What metal is most magnetic? Is the most magnetic material a metal?


Replies:
The things that produce the strongest magnetic field are electromagnets -- they can produce magnetic fields of tens of teslas (40-50T). The tesla, T, is a unit of magnetic field.

For permanent magnets, there are exotic mixtures of rare-earth metals that can hold a magnetic field of 2 or more teslas. Typical mixtures include Iron-Neodymium-Boron and Aluminum-Nickel-Cobalt, with samarium-cobalt, and other ceramics also possible. Permanent magnets start as a 'blank slate' or sorts, and have to be magnetized, so you need a stronger field to apply to them first (such as an electromagnet).

When you ask what 'material is the most magnetic', this actually encompasses several properties. Magnetization, or saturation magnetization, refers to how well a material can become magnetized. Some materials stay magnetized after being exposed to a field (these are called permanent magnets). Another property, magnetic permeability, refers to how well a material can be penetrated by a magnetic field. There are many other properties of materials related to magnetic fields. Together, they add up to the 'magnetic behavior' we can observe. In other words, magnetism is enormously complicated. In fact, some materials respond to magnetic fields in unexpected ways -- including a 'magnetically levitating frog' movie that you can easily find through Google. For a quick, but good primer on magnetics, try this: http://info.ee.surrey.ac.uk/Workshop/advice/coils/mu/index.html It's not an easy read, though -- you didn't include your grade level, so it may or may not be appropriate for you.

Also, as a side note, in space, some stars can produce magnetic fields of millions of teslas. These are a special case of electromagnets, in a way.

Hope this helps,
Burr Zimmerman


Hi Steven,

The term "most magnetic" is not very specific, but I will try to answer what I think you may mean. If you are asking what material is most strongly attracted to a magnet, then the answer is probably ordinary iron or steel.

If you are asking what material makes the strongest magnets, then the answer is Neodymium magnets, which are made of a metallic-appearing chemical compound (not technically an actual metal) composed of Neodymium, Iron and Boron, with the chemical formula of Nd2Fe14B. True metal magnets made of a metallic alloy called "Alnico" (a mixture, or alloy, of Aluminum, Nickel and Cobalt) were once considered to be the strongest magnets, but are not as strong as Neodymium magnets.

There are some magnets made of a "ceramic-like" material that is not metallic at all, called "Ferrite". This material does not make strong magnets, but it has the advantage of extreme low cost.

Regards,
Bob Wilson.


It is not possible to make a unique designation because the magnetic properties of a material depends upon a lot of different factors: composition; temperature; history of the particular material; impurities; the list is long...

The "cause" of magnetism in the most naive sense is the number or unpaired electrons. This is a real oversimplification because orientation of magnetic domains and how the atoms are oriented both come into play, but keeping it simple, you would want the maximum number of unpaired "f" and "d" electrons, so elements like gadolinium (Gd), or the radioactive actinide curium (Cm) would be candidates. However, as pointed out, this is only an estimate because a lot of factors come into play.

Vince Calder



Click here to return to the Material Science Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory