A data write current from a pinned layer to a free layer is larger than a
data write current from the free layer to the pinned layer. A data read
current is smaller in value than the data write current. In the case
where a difference in data read current between a high-resistance state
and a low-resistance state is relatively small, a sense amplifier is
connected so that the data read current flows from the pinned layer to
the free layer, namely from a source line to a bit line.