Ferroelectric hard disk system

1. An apparatus comprising:

a ferroelectric medium comprising a bottom electrode and a ferroelectric layer disposed on the bottom electrode; and

a head disposed above the ferroelectric medium, the head being operative to write and reproduce information on the ferroelectric layer,

wherein the head comprises:

a substrate;

an insulating layer disposed on the substrate;

a reading head disposed on the insulating layer, the reading head including a source, a drain, and a channel region;

a separation layer disposed on the reading head; and

a writing head disposed on the separation layer.

2. The apparatus of claim 1 , wherein the source and the drain are disposed on opposite sides of the insulating layer, and the channel region is disposed between the source and the drain.

3. An apparatus comprising:

a ferroelectric medium comprising a bottom electrode and a ferroelectric layer disposed on the bottom electrode; and

a head disposed above the ferroelectric medium, the head being operative to write and reproduce information on the ferroelectric layer,

wherein:

the head comprises a reading head including a source, a drain, and a channel region between the source and the drain;

the head is operative to reproduce information on the ferroelectric layer according to an amount of drain current flowing between the source and the drain;

when an information unit of the ferroelectric layer has a dipole with a downward polarization direction, electron depletion occurs in the channel region and a first drain current flows between the source and the drain; and

when an information unit of the ferroelectric layer has a dipole with an upward polarization direction, electron accumulation occurs in the channel region and a second drain current flows between the source and the drain, the second drain current being greater than the first drain current.