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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
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Update: June 2012
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