A spectrum-generating algebra for particles of spin 1/2

Spectrum-generating algebra techniques developed in previous works to deal with the problem of one particle in a potential are extended to deal with particles of spin 1/2. The method is illustrated considering the Pauli and Dirac equations with a Coulomb potential. The way to deal with some other potentials is indicated. In the Pauli equation an intrinsic electric dipole moment term is included. It is particularly remarkable the simplicity with which the solutions are obtained. (author)