Role of boron diffusion in CoFeB/MgO magnetic tunnel junctions

Mukherjee, Sumanta and Knut, Ronny and Mohseni, SM and Anh Nguyen, TN and Chung, S and Le, Tuan Q and Akerman, Johan and Persson, Johan and Sahoo, Anindita and Hazarika, Abhijit and Pal, Banabir and Thiess, Sebastian and Gorgoi, Mihaela and Kumar, Anil PS and Drube, Wolfgang and Karis, Olof and Sarma, DD (2015) Role of boron diffusion in CoFeB/MgO magnetic tunnel junctions. In: PHYSICAL REVIEW B, 91 (8).

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Abstract

Several scientific issues concerning the latest generation read heads for magnetic storage devices, based on CoFeB/MgO/CoFeBmagnetic tunnel junctions (MTJs) are known to be controversial, including such fundamental questions as to the behavior and the role of B in optimizing the physical properties of these devices. Quantitatively establishing the internal structures of several such devices with different annealing conditions using hard x-ray photoelectron spectroscopy, we resolve these controversies and establish that the B diffusion is controlled by the capping Ta layer, though Ta is physically separated from the layer with B by several nanometers. While explaining this unusual phenomenon, we also provide insight into why the tunneling magnetoresistance (TMR) is optimized at an intermediate annealing temperature, relating it to B diffusion, coupled with our studies based on x-ray diffraction and magnetic studies.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC
Additional Information:	Copy right for this article belongs to the AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Keywords:	ENERGY PHOTOELECTRON-SPECTROSCOPY; ROOM-TEMPERATURE; INTERNAL HETEROSTRUCTURE; MAGNETORESISTANCE; NANOCRYSTALS
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	21 Apr 2015 06:44
Last Modified:	21 Apr 2015 06:44
URI:	http://eprints.iisc.ac.in/id/eprint/51304

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