Dependence of noise in magnetic tunnel junction sensors on annealing field and temperature

Authors

Sy-Hwang Liou, University of Nebraska-LincolnFollow
Rui Zhang, University of Nebraska - Lincoln
Stephen Russek, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
L. Yuan, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
Sean T. Halloran, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
David P. Pappas, National Institute of Standards and Technology, Boulder, Colorado 80305, USA

Date of this Version

3-7-2008

Comments

Published in JOURNAL OF APPLIED PHYSICS 103, 07E920 2008. Copyright © 2008 American Institute of Physics. Used by permission.

Abstract

The minimum detectable field of magnetoresistive sensors is limited by their intrinsic noise. Magnetization fluctuations are one of the crucial noise sources and are related to the magnetization alignment at the antiferromagnetic-ferromagnetic interface. In this study, we investigated the low frequency noise of magnetic tunnel junctions (MTJs) annealed in the temperature range from 265 to 305 °C and magnetic fields up to 7 T, either in helium or hydrogen environments. Our results indicate that the magnetic fluctuators in these MTJs changed their frequency based on annealing field and temperature. The noise of the MTJs at low frequency can be reduced by annealing in high magnetic field (7 T) and further improved by annealing in a hydrogen environment.