AVS 46th International Symposium
    Magnetic Interfaces and Nanostructures Technical Group Wednesday Sessions
       Session MI-WeA

Invited Paper MI-WeA5
CPP-GMR for Magnetoelectronic Memory

Wednesday, October 27, 1999, 3:20 pm, Room 618/619

Session: Giant Magnetoresistance
Presenter: K. Bussmann, Naval Research Laboratory
Authors: K. Bussmann, Naval Research Laboratory
G. Prinz, Naval Research Laboratory
B. Bass, Naval Research Laboratory
S.-F. Cheng, Naval Research Laboratory
D. Wang, Nonvolatile Electronics, Inc.
J. Daughton, Nonvolatile Electronics, Inc.
Correspondent: Click to Email
Current perpendicular-to-plane giant magnetoresistance (CPP-GMR) has been demonstrated to provide enhanced GMR relative to that measured using the current-in-plane (CIP) geometry with similar multilayer architectures. We have been pursuing this advantage in work performed at the Naval Research Laboratory in developing a new non-volatile magnetic memory compatible with existing Si-CMOS technology. The functionality of this approach improves as the device dimension is reduced to sub-micrometer levels. At these dimensions the micromagnetic switching processes are strongly influenced by edge effects and it is important to include these terms, along with intrinsic magnetic materials properties, to obtain stable '0' and '1' configurations. We will show our results on circular disk devices that stabilize the magnetization in right or left-handed helicity. The devices are constructed as magnetic layers separated by non-magnetic spacer layers. Magnetic layers are alternately rendered 'hard' and 'soft' by varying the thickness of the layers as 'thick' or 'thin', respectively. The residual magnetic pole density at the device edge is minimized by the nature of the parallel alignment of the magnetization to the circumference of the disk, an effect driven by the exchange coupling intrinsic to each layer. Parallel and antiparallel helicity orientations of the magnetization are obtained by flowing current through the device, allowing programmability to '0' (parallel) and '1' (antiparallel) states. We show and interpret switching data on devices ranging from 0.25 - 0.6 micrometers in diameter and present an analysis of utility of these structures in CPP-GMR magnetoelectronic memory.