Minutes: An official the official record of the proceedings at a meeting of an organization. It is generally accepted as an official document, and, as such, can be used in eventual disputes arising from matters discussed therein.
Memorandum: Generally, memorandum, which is frequently referred to colloquially as "memo", is a record prepared on teh basis of what has been orally discussed. As such, it is sometimes used instead of minutes, but it does not impliy any officialdom.
