Mangetoresistive RAM (MRAM) is a unique creation by Philips, which allows a self-destruct sequence to initiate and destroy the device holding information. So if you are prone to walking around with top-secret government information in a small handheld device encased with MRAM chips, no need to fear. When the casing is broken, the self-destruction begins.
The MRAM skips password or biometric protection, and is made to just destroy the electronic storage device. The MRAM is wrapped in two layers of metallic foil that keep a gathering flux with a magnetic closed loop of electricity. If the first layer of foil is broken, the all the flux goes wild and magnetically erases everything on the storage device.
MRAM technology seems like a good idea, but quite hard to implement. The use of MRAM protecting a hard disk drive makes a lot of sense. A data thief busts open a computer, tries to grab the disk drive, but the MRAM is broken and magnetically erases the drive. So when the disk drive is connected to a new computer it will be completely empty.
It is a novel and unique idea from Philips, but most likely not the best way to protect sensitive information.