Hitachi halves hard drive head size

Hitachi’s new head may be tiny – 30-50nm in size, one two-thousandth of the thickness of a human hair – but the technology it’s based on is something of a mouthful: Current Perpendicular-to-the-Plane Giant Magneto-Resistive (CPP-GMR). In practice that means the heads are based conduction through metal rather than an insulator, as is the case with today’s quantum-tunneling based Tunnel Magneto-Resistive (TMR) hard drive heads. The CPP-GMR head’s lower electrical resistance allows it to detect smaller changes in the disc platter’s magnetic field, reduced as drive makers ramp up disks’ data storage density.