MRAM technology
MRAM or a magnetic random access memory using magnetic tunnel junction transistor -1 (1T-1MTJ) architecture, wherein the magnetic material is a ferromagnetic "state" as a data storage element. Since MRAM uses magnetic storage state (rather than over time "leak" charge), so MRAM can provide very long data retention times (20 + years) and unlimited endurance. Switching magnetic polarization (Write Cycle) is the result of generating a pulse current (see FIG. 1) of the electromagnetic tunnel junction (MTJ) in the upper and the lower wire.
Figure 1: a magnetic tunnel junction (MTJ)
Current pulse caused by the relevant field H changes the polarization of the free layer of ferromagnetic material. This magnetic switch does not require displacement of atoms or electrons, which means there is no wear mechanism associated with the MRAM. The magnetic moment of the free layer with respect to the fixed layer changes the impedance of the MTJ (see FIG. 2).
FIG 2: MRAM magnetic tunnel junction (MTJ) storage element
This impedance change indicates the status of the data ( "1" or "0"). Sensing (read cycle) is achieved by measuring the impedance of the MTJ (FIG. 3). Read cycle MRAM devices are non-destructive, and relatively fast (35ns). Reading is performed by applying a very low voltage across the MTJ done to support the operation member unlimited service life.
FIG 3: MRAM read and write cycles
FRAM technology
Or FRAM ferroelectric random access memory using a ferroelectric capacitor -1 transistor (1T-1FC) architecture, which uses a ferroelectric material as a storage device. Intrinsic electric dipole convert these materials under the action of a polarity opposite to an external electric field. Need to change the ferroelectric polarization state dipole (Ti4 + ions located in the octahedral oxygen) moves (in the case of Pb (Zr, Ti) O3) is responsive to the electric field (FIG. 4). Or other free of charge accumulation with time and temperature of the ion motion will prevent this defect, these defects lead to dipole relaxation over time, leading to fatigue.
FIG 3: FRAM atomic structure of FIG. 4: FRAM data states
FRAM is a read operation is destructive, because it requires the switching to polarization state sensing its state. After the initial reading, the reading operation must be restored to its original polarization state, which increases the read cycle time.
Figure 5: FRAM read / write cycles
FRAM read and write cycle requires an initial "pre-charge" time, which may increase the initial access time.