Ferroelectric random access memory (FRAM) stores computer data using a special "ferroelectric film" which has the ability to change polarity quickly. It is able to retain data even when the power is not on, so it’s classified as non-volatile memory. Ferroelectric memory works without batteries and consumes little power when information is being written or rewritten to the chip. The performance of random access memory is combined with the abilities of read-only memory in ferroelectric memory. It is used for smart cards and mobile devices such as cell phones because little power is used and the memory chips are hard to access by someone tampering with them.
A ferroelectric memory chip operates by using a lead zirconate titranate film to alter an electrical field around it. The atoms in the film change the electrical polarity to positive or negative, or vice versa. This causes the film to behave as a switch that is compatible with binary code and can allow for data to be stored efficiently. The polarity of the film stays the same when the power is off, keeping the information intact and allowing the chip to work without much energy. Ferroelectric memory chips will even keep data if the power is suddenly turn off such as in a blackout.
Compared to dynamic random access memory (DRAM) and electrically erasable programmable read-only memory (EEPROM), ferroelectric memory consumes 3,000 times less power. It is also estimated to last 10,000 times longer since information can be written, erased, and rewritten many times. A dielectric layer is used in DRAM, but a ferroelectric layer is used in place of it for FRAM. The structure of the different memory chips is otherwise very similar.
Also known as FeRAM, ferroelectric memory can write much faster than other memories. The write speed has been estimated to be almost 500 times faster than with an EEPROM device. Scientists have used electron microscopes to make images of the electric fields on the memory chip’s surface. Using this technique, they can measure materials that allow polarization to be controlled at atomic scales, in order to create memory chips that work even faster.
Ferroelectric memory is more energy efficient than other types of computer memory. It also safer to use and store data on because important information won’t be lost as easily. It is suited for use in cell phones and in radio frequency identification (RFID) systems. The memory chips can also rewrite data many more times, so the memory will not wear out and need to be replaced in a short amount of time.