memory device according to one embodiment of the present invention the x axis represents the writing current lb ma and the y axis represents the magnetic resistance r ohm or u03c9 fig6 b proves experimentally the feasibility of utilizing one electrical conductive line to perform both the writing operation and the reading operation for a magnetic memory device according to the present invention fig6 c shows a magnetization curve of a magnetic memory device having both the bit lines and the word lines according to this curve the magnetic memory device switches its state when the writing current is about 2 5 ma or higher comparing with fig6 a one would appreciate that when the writing current reaches the same level i e 2 5 ma in this example a magnetic memory device will switch its states with or without a word line it should be appreciated that according to the above curves it is possible that a memory device requires only the bit line to perform its writing process the word line of conventional magnetic memory may be eliminated and therefore the overall structure of the memory device is simplified and the writing current is reduced reference is now made to fig7 a and 7b a magnetic memory device 700 according to one embodiment of the present invention comprises a memory cell 710 a row of bit lines 720 electrically coupled to the memory cells 710 only one memory cell is shown as an example for illustration to perform the reading and writing operations an array of gate elements such as switch transistors 730 only one switch transistor is shown as an example for illustration is provided with its collector 732 connected.