As far as I’m aware CDs use gold or silver neither of which exhibit any magnetic properties other than in extreme circumstances.
By way of interest though.
Scientists have recently managed to create magnetic particles of gold, silver and copper but only at nanometric scale and only by way of an intermediate process that involves surrounding the normally non-magnetic atoms with organic molecules.
They do remain permanently magnetic though at the end of the process, even at room temperature.
The particles are only 2nm across so you’d need a fair few of them to make a magnetic CD.