Magnetic recording properties of SmCo5

Extremely high coercivity magnetic recording materials are being evaluated for use in secure magnetic documents. Commercially available SmCo5particles were milled in a standard binder solution, and coated onto polyester film, to make experimental magnetic recording tapes. Selected magnetic properties and low-bit-density recording characteristics were determined for two SmCo5tapes with intrinsic coercivities of 8.9 and 11.3 kOe, and compared with two barium ferrite tapes with coercivities of 4.1 and 5.2 kOe. Both SmCo5tapes had too high coercivity for an iron-cobalt core head to record. The SmCo5tapes had poorer signal output and alteration resistance than the lower coercivity barium ferrite tapes.