1. A magnetic random access memory comprising: a first electrically conductive line; a magnetic memory cell coupled in series to the first electrically conductive line, the magnetic memory cell having a magnetic resistance that is switched between a minimum magnetic resistance and a maximum magnetic resistance according to directions of magnetization vectors stored in the magnetic memory cell; a second electrically conductive line; a reference magnetic memory cell coupled in series to the second electrically conductive line, the reference magnetic memory cell having a predetermined magnetic resistance; and a resistive element coupled in series to the reference magnetic memory cell, a total resistance across the reference magnetic memory cell and the resistive element being set between the minimum magnetic resistance and the maximum magnetic resistance.