Conductive Atomic Force Microscopy of Small Magnetic Tunnel Junctions With Interface Anisotropy

Author

Piotrowski, Stephan K. ; Bapna, Mukund ; Almasi, Hamid ; Wei-Gang Wang ; Tryputen, Larysa ; Ross, Caroline A. ; Mingen Li ; Chia-Ling Chien ; Majetich, Sara A.

Author_Institution

Dept. of Phys., Carnegie Mellon Univ., Pittsburgh, PA, USA

Volume

51

Issue

11

fYear

2015

Firstpage

1

Lastpage

4

Abstract

Magnetization reversal in CoFeB/MgO/CoFeB magnetic tunnel junctions with perpendicular magnetic anisotropy was studied as a function of both diameter (from 87 to 500 nm) and voltage (from -900 to 900 mV) using a conducting atomic force microscope. We found that the tunneling magnetoresistance near zero voltage was ~100% for all device sizes. The coercivity of the top CoFeB layer was identical within experimental error for the sizes between 158 and 500 nm but was smaller for 87 nm devices. This suggests a transition from domain-wall-nucleation-driven magnetization reversal to coherent rotation between 87 and 158 nm.

Keywords

atomic force microscopy; boron alloys; cobalt alloys; coercive force; iron alloys; magnesium compounds; magnetic domain walls; magnetic multilayers; magnetisation reversal; nucleation; perpendicular magnetic anisotropy; tunnelling magnetoresistance; AFM; CoFeB-MgO-CoFeB; CoFeB-MgO-CoFeB magnetic tunnel junctions; coherent rotation; conductive atomic force microscopy; device sizes; domain-wall-nucleation-driven magnetization reversal; interface anisotropy; perpendicular magnetic anisotropy; size 87 nm to 500 nm; top CoFeB layer coercivity; tunneling magnetoresistance; voltage -900 mV to 900 mV; Coercive force; Magnetic field measurement; Magnetic tunneling; Perpendicular magnetic anisotropy; Switches; Tunneling magnetoresistance; Conductive AFM; Conductive atomic force microscopy (C-AFM); magnetic tunnel junction; magnetic tunnel junction (MTJ); perpendicular magnetic anisotropy; perpendicular magnetic anisotropy (PMA); voltage controlled anisotropy; voltage-controlled anisotropy;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2015.2434798

Filename

7109902