Spintronic devices are devices that utilizes the properties of electrons to transfer, process and store information. Electronic devices utilizes the electrical charge of an electron to encode data. Spintronic devices use another fundamental property known as spin, which is the basic angular momentum of the electron. Spintronics has many advantages over conventional electronics. Electronics necessitate specialized semiconductor materials in order to control the flow of charge through the transistors. But spin can be calculated very simply in collective metals such as copper. Less energy is required to change spin than to produce a current to maintain electron charges in a device, so spintronics devices use less power.
Spin states can be set rapidly, which makes transporting data quicker. And because electron spin is not dependent on energy, spin is non-volatile information directed using spin remains stable even after loss of power.
A hard disk stores data as ones and zeros encoded magnetically on rotating disk platters. The magnetic field is produced when electrons flow over wire coils mounted in the drive write heads which move across the face of the platters, altering the alignment of the magneto-sensitive particles on the flatter surface. Reversing the electron flow reverses the field; the two directions signify one and zero. To read from the disk the process works in inverse.A GMR drive head contains of two ferromagnetic layers, one with a stable magnetic field direction and the other free to align with the magnetic field encoded , with a non-magnetic layer inserted in between.When an electron passes through a magnetic field its spin state may change, well-known as scattering. Where electrons have random, scattered spin states this produces larger resistance to electric current. By aligning electrons' spin state to that of the magnetic field in the coatings of the drive head, GMR technology naturally reduces resistance, speeding up data transfer.