Any storage medium that utilizes magnetic patterns to represent information is considered magnetic media. Good examples of a magnetic media and magnetic storage is a tape drive, floppy diskette, and hard drive.
Above is an example of the read/write head inside a hard drive. The electromagnetic write head polarizes tiny sections of the hard drive so they face up or down ("North" or "South") to represent the binary digits 1 or 0. The read head detects the polarization of each section of the drive to understand the data that was written.