Conductive atomic force microscopy of small magnetic tunnel junctions with interface anisotropy

S. Majetich, S. K. Piotrowski, M. Bapna, S. D. Oberdick, M. Li, C. Chien, L. Tryputen, C. Ross, H. Almasi, Weigang Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Magnetic anisotropy at the interface between a thin metallic ferromagnet and an insulating oxide layer has been used to make devices with voltage-controlled switching [1-4]. Sharp switching thresholds have previously been reported for devices below 100 nm [3], but questions remain about the size dependence of the switching thresholds and the stability with respect to thermal fluctuations. Here a series of CoFeB (1.5 nm)/MgO (2 nm)/CoFeB (0.8 nm) magnetic tunnel junctions (MTJs) with interface anisotropy were characterized using conductive atomic force microscopy (CAFM) to measure their resistance as a function of the perpendicular magnetic field and bias voltage. With a lithographically patterned MTJ, there are two new features, relative to prior work applying this technique to nanoparticles [5]. First, both magnetic layers have a known crystallo-graphic orientation, which in this case leads to perpendicular magnetic anisotropy and increased squareness in the hysteresis loops. Second, features varying over a wide range of device diameters but the same tunnel barrier thickness have been prepared, enabling the systematic determination of size-dependent properties.

Original languageEnglish (US)
Title of host publication2015 IEEE International Magnetics Conference, INTERMAG 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Print)9781479973224
DOIs
StatePublished - Jul 14 2015
Event2015 IEEE International Magnetics Conference, INTERMAG 2015 - Beijing, China
Duration: May 11 2015May 15 2015

Other

Other2015 IEEE International Magnetics Conference, INTERMAG 2015
CountryChina
CityBeijing
Period5/11/155/15/15

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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