A memória Flash usa transistores de porta flutuante para armazenar dados, em vez do método magnético usado pelos discos rígidos. A presença de um campo magnético não é necessariamente um problema para um SSD, mas a taxa de mudança do fluxo magnético pode causar dano :
CFs [Compact Flash drives] aren't magnetic media, so they can't be erased like, say, a floppy disk or a hard drive. However, depending on the strength of the magnetic field, a CF isn't completely safe. For instance, if you were to do an MRI of your CF (or any other piece of sensitive electronic circuitry, for that matter), it would be toast. It's not simply the strength of the magnetic field that matters, so much as the rate at which the field changes. If you go from strong field to no field very quickly or vice versa, then the change in magnetic flux can generate small voltages over wires, traces, etc. If the voltages are high enough, then they can cause damage. I don't know, practically, in the real world, what sources of magnetic fields might pose a danger to a CF -- or a camera -- or a lens.