Study of Noise in Current-Perpendicular-to-Plane Giant Magnetoresistance Devices with a Current Screen Layer

The noise in current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices with a current screen layer (CSL) is investigated to clarify the noise generation mechanism. The noise intensity is greatly enhanced in the antiparallel magnetization configuration due to spin torque effects. In ad...

Full description

Saved in:
Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 50; no. 3; pp. 033002 - 033002-4
Main Author Nakao, Ryota
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.03.2011
Online AccessGet full text

Cover

More Information
Summary:The noise in current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices with a current screen layer (CSL) is investigated to clarify the noise generation mechanism. The noise intensity is greatly enhanced in the antiparallel magnetization configuration due to spin torque effects. In addition, the noise intensity increases as the temperature is reduced because thermal spin fluctuations decrease. Furthermore, the noise intensity increases when spins flow to the free layer because the magnetization of the free layer fluctuates easily. These results imply that noise is generated by fluctuations in the magnetization of the free layer caused by spin torque. Moreover, some CPP-GMR devices with a CSL have some peaks in plots of noise intensity against applied magnetic field. These peaks are thought to be related to the current-induced field and magnetization fluctuations at the edge of the device.
Bibliography:Circuit for measuring noise in a CPP-GMR device with a CSL. Schematic diagram of a CPP-GMR device with a CSL. Noise in parallel and antiparallel configurations in a CPP-GMR device with a CSL measured at 77 K. Magnetization fluctuations for parallel and antiparallel configurations. Noise at 77 and 294 K in a CPP-GMR device with a CSL. Measurements were performed in the antiparallel configuration. Magnetization fluctuations at low and high temperatures. Noise for positive and negative currents in a CPP-GMR device with a CSL (antiparallel configuration). Magnetization fluctuations in pinned and free layers. Peaks in noise intensity against applied field plots. Noise peaks for several currents. Mechanism for peaks in noise intensity plots.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.50.033002