16:00 〜 16:15
▲ [20p-B101-7] 3D racetrack memory devices formed from freestanding magnetic heterostructures
キーワード：memory device, freestanding, 3D
Magnetic random access memory (MRAM) is a promising candidate for the realization of next generation memory devices due to its high performance and non-volatility. Whereas MRAM stores individual bits in magnetic tunnel junction devices, Magnetic Racetrack Memory (RTM) encodes data in a series of magnetic domain walls (DW), that are manipulated by electric current pulses within a single racetrack element. Thus, RTM goes beyond MRAM and has the potential to realize vastly greater data capacities with much higher speeds. To date, most studies have focused on 2D RTM while going from 2D to 3D which allows higher data density would make RTM more attractive. However, it is difficult to deposit the required thin films uniformly on pre-patterned 3D structures by conventional methods such as magnetron sputtering. To overcome these difficulties, here, we show, by using a freestanding film transfer technique, complex heavy metal/ferromagnetic (HM/FM) heterostructures can be transferred to a given substrate, here a sapphire substrate, with the magnetic properties largely intact. We further realize a 3D RTM device by transferring the magnetic heterostructures onto a sapphire substrate on which 3D protrusions of different heights were pre-formed. We show that the current-induced domain wall motion (CIDWM) can be controlled by the local geometry in such 3D RTMs.