Can aluminum be magnetised?

As a materials science expert, I have a deep understanding of the properties and behaviors of various materials, including metals like aluminum. Let's delve into the question of whether aluminum can be magnetized.

Firstly, it's important to understand the different types of magnetic materials. There are four main categories: ferromagnetic, paramagnetic, diamagnetic, and antiferromagnetic. Ferromagnetic materials are those that are strongly attracted to a magnet and can become magnetized themselves, retaining magnetism even after the external magnetic field is removed. Paramagnetic materials, on the other hand, are weakly attracted to a magnet and do not retain magnetism once the external field is gone. Diamagnetic materials are weakly repelled by a magnet, and antiferromagnetic materials exhibit a complex behavior where the magnetic moments of atoms align in a way that cancels out the overall magnetism.

Aluminum falls into the category of paramagnetic materials. This means that it can be influenced by a magnetic field, but the effect is quite weak. The property that describes how a material responds to an external magnetic field is called magnetic susceptibility. For aluminum, this value is indeed around 2.2 x 10^-5, which is a very small number indicating a weak response to a magnetic field.

When an external magnet is brought near aluminum, it will induce a magnetic field within the aluminum, but the effect is so subtle that it is not noticeable to the human eye or touch. This is in stark contrast to ferromagnetic materials like iron, nickel, or cobalt, which are strongly attracted to magnets and can become magnetized quite noticeably.

In a laboratory setting, the paramagnetic properties of aluminum can be measured using sensitive equipment. Scientists use techniques such as the Gouy balance or the Faraday balance to measure the magnetic susceptibility of materials. These methods rely on the principle that a paramagnetic material will experience a force in a magnetic field gradient, which can be measured and used to calculate the magnetic susceptibility.

However, in everyday situations, you would not expect to see aluminum being attracted to magnets or becoming magnetized in a way that is perceptible. The weak interaction between aluminum and a magnet is not sufficient to cause any significant movement or change in the aluminum's behavior.

It's also worth noting that the ability of a material to be magnetized is not a binary property; it exists on a spectrum. While aluminum is at the weak end of this spectrum, it still exhibits some level of magnetism under the right conditions, albeit not in a way that is practical or noticeable in most circumstances.

In conclusion, aluminum can technically be magnetized due to its paramagnetic nature, but the effect is so minimal that it is not practical or noticeable in everyday life. The magnetic susceptibility of aluminum is very low, and any induced magnetism would require sensitive laboratory equipment to detect.

Aluminium is paramagnetic, so external magnets will induce a magnetic field in it. However the magnetic susceptibility is only 2.2 10 so I'd be surprised if the induced magnetism would be high enough to be noticable. Normally you can only measure paramagnetism in the lab with sensitive equipment.