When powerful magnets are in close proximity, they can distort or destroy recorded cassette recordings. Even a refrigerator magnet is effective. Cassette tapes should never be stored near magnets of any kind. The magnetic field created by these objects can remain active for many years, so if you have tapes from devices that were used in other states or countries, it's best to avoid putting them in the same container as your refrigerator.
Because of the magnetic nature of the tapes, strong magnets can distort and even erase the data on them. Even a normal ceramic (refrigerator) magnet has enough strength to destroy the tape if kept in close contact. The best option is to remove any metal objects that might be used to store data with magnets.
Tapes were once the most popular medium for storing data, but now they are being replaced by more modern media such as hard drives and optical discs. However, tapes remain useful for transporting large amounts of data over long distances or across networks.
The magnetic coating on modern recording devices is usually very thin, so even if you put something with a strong magnet inside your laptop, it won't be able to read data from farther away than a few hundred microns. But old-style magnetic tapes have thicker coatings which allow them to retain their shape even when removed from the device that recorded them. Thus, if you leave a tape in proximity to a strong magnet, it could be damaged or erased beyond repair.
If you leave a tape in proximity to a strong magnet, it could be damaged or erased beyond repair.
The only way to be sure that no data will be lost is not to expose any magnetic recordings to a strong magnet.
Even a normal ceramic fridge magnet is strong enough to destroy the tape if kept in close contact with it. Tape manufacturers recommend that any metal objects being stored on or along with the tape be removed.
Tape machines read information from the tape by sensing variations in its magnetic field. This works best if there are no other sources of magnetic interference in proximity to the tape. A strong magnet placed near the head of the machine could cause errors in the reading process. If you have multiple types of recording media in your archive, see our article on Multimedia storage methods.
Cassette tapes and floppy disks use magnetic materials to store information and may be wiped with a magnet. If a powerful enough magnet comes close enough to the tape or disk, it will jumble the data. This "erases" the tape or disk. If the magnet is strong enough and close enough, it will work. However, if there are other parts of the tape or disk that don't contain data, they will be affected by the magnet as well and become unreadable.
There are two types of magnets used for erasing tape: bar magnets and ring magnets. Bar magnets are long strips of material with their ends joined to form a rectangle. Ring magnets are circles of metal with poles facing out. Data on a tape or disk can be read by a device called an eraserette. It uses a similar magnet to erase the tape or disk, but instead of being strong enough to erase entire tracks, it is designed to erase small sections of tape or disk at a time. These magnets are available from tape library manufacturers and online retailers such as Amazon.com.
Magnetic storage media such as tape and disk suffer from a phenomenon known as "magnetic decay". This means that over time, the magnetic properties of the medium will decrease, leading to increased error rates when reading back data from it. For this reason, all magnetic storage media should not be erased using magnets or else the data will be lost forever.