What is the sl unit for magnetic field?

Different units are used. From Wikipedia: "The term [magnetic field] is used for two distinct but closely related fields denoted by the symbols B and H, where H is measured in units of amperes per meter ... B is measured in teslas (symbol:T) and newtons per meter per ampere(symbol: N·m−1·A−1 or N/(m·A)) in the SI. ..."