On hard disks, the data is stored magnetically. This storage is permanent? it is retained when you turn off the computer. However, since a read / write head must be brought to the respective storage location for storing and reading the data, this method is relatively slow.
In contrast, the computer's DRAM RAM stores electrical charges in tiny capacitors. This process is faster, but the charge in the capacitors needs to be refreshed several times a second. Therefore, the computer "forgets" the contents of this memory when the power supply is interrupted and must be rebooted at the next use.
In the MRAM memories, the data is stored magnetically and therefore permanently. The respective orientation of the magnetic field in a "cell" corresponds to either the information value zero or one. In recent years, efforts have been made to be able to reverse the magnetic fields in these information units faster. This has been achieved with short electron beam pulses. However, the speed of this process is limited by an undesirable effect: If you turn the magnetic field too fast, you have the same orientation after rotation as before. display
Rasing and his colleagues have now succeeded in generating "shaped" magnetic field pulses with the help of two laser pulses, which precisely reverse the orientation in an information unit. They achieved a switching time of one-fifth of a billionth of a second. This corresponds to a data write rate of five gigahertz.Axel Tilleman