What causes metals to become magnetically charged? And can you force a metal to have its north or south poles on certain sides?

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What causes metals to become magnetically charged? And can you force a metal to have its north or south poles on certain sides?

In: Physics

2 Answers

Anonymous 0 Comments

There are two types of metals with respect to magnetic properties: diamagnetic and paramagnetic.

First, electrons in atoms have a spin to them (for metals, they exist in the d-orbital) and this gives electrons a magnetic property. If the electrons are paired; however, their spin and therefore magnetic property is cancelled out.

Diamagnetic means all the electrons per atom are paired. These metals do not exhibit a strong interaction with magnetic fields.

Paramagnetic means there are some electrons that are unpaired per atom. These metals exhibit a strong interaction with magnetic fields.

Chunks of metal like iron, made up of many atoms, [Ar] 3d6 4s2 (you find out if if it’s it’s paramagnetic or diamagnetic by plotting the electron configuration with the orbitals and seeing if there are any unpaired electrons), that are paramagnetic do not exhibit magnetic properties until they are put through a strong magnetic field or electric current because while each atom exhibits magnetic properties the whole “chunk” of iron will not unless each atom is aligned in the same direction. Then the block of iron becomes a magnet. You can apply the current or magnetic field in a particular direction to change the poles as well.

Anonymous 0 Comments

There are actually (at least) _four_ types of material with respect to magnetic properties, and neither of the types described by the other response explain permanent magnetism which is what the OP is referring to. Diamagnetism and paramagnetism only result in a magnetisation within a magnetic field – as soon as the field is removed, the materials are demagnetised.

Permanent magnetism is a property of certain materials where the material retains its magnetisation even after an external field is removed. This property arises because of something known as ‘long-range order’ – essentially, certain metal ions have unpaired electrons in d orbitals that are so large that they can interact with electrons in neighbouring atoms. This means that, rather than atoms acting as individual magnets (as is the case in diamagnetism and paramagnetism), changes in the magnetisation of one atom affects the magnetisation of other atoms, and the result of these interactions beteen atomic magnetic fields results in large-range order. When the magnetic field is removed, individual atoms are no longer able to go back to having a random magnetisation because the interactions with the magnetisations of neighbouring atoms constrains them. There are a number of different subtypes of permanent magnetism which depend on the way the magnetic fields of different atoms interact, including ferromagnetism (where the magnetisations of all magnetic atoms are aligned) and ferrimagnetism (where the magnetisations are not aligned, but there is a dominant alignment), antiferromagnetism (where the magnetisations are not aligned and there is no dominant alignment), and canted antiferromagnetism (where the magnetisations are theoretically not aligned and have no dominant alignment, but crystal-field effects result in a small alignment).