Abstract

We produced a large uniaxial anisotropy (H<formula><tex>$_{\rm k}$</tex></formula>) in ultra-thin (1.2 to 2.4 nm) soft ferromagnetic layers through the oblique deposition of a nm-thick metallic underlayer. Fe, Ni and Ni<formula><tex>$_80$</tex></formula>Fe<formula><tex>$_20$</tex></formula> (Permalloy) films deposited on a 5 nm thick Nb layer grown at an oblique angle (up to 60&#x00B0;) exhibit a H<formula><tex>$_{\rm k}\approx$</tex></formula>40-500 Oe and have properties that are nearly ideal for use as a fixed layer in magnetic devices such as for magnetic memory. A much higher induced H<formula><tex>$_{\rm k}$</tex></formula> is observed in Ni (500 Oe) and Fe (300 Oe) compared to NiFe (40 Oe). We used this technique to increase H<formula><tex>$_sw$</tex></formula> by 3X-5X in an array of pattered Fe or NiFe bits, and achieved an excellent relative switching distribution of <formula><tex>$\approx$</tex></formula>0.05-0.06. We also controllably enhanced the H<formula><tex>$_{\rm k}$</tex></formula> in the fixed layer of patterned spin-valve devices for superconducting memory (JMRAM) and produced a large difference in H<formula><tex>$_{\rm sw}$</tex></formula> between the fixed and free layers. Different spacer layers between the Nb and the magnetic layers were found to either transmit (Ru) or reduce (Cu, Ru/Al, ion-milled Ru) the effect of the oblique Nb. This technique was also effectively used in synthetic antiferromagnet (SAF) structures, and therefore has the potential to eliminate the need for an antiferromagnetic-pinning layer when it degrades magnetic device performance.

Original languageEnglish (US)
JournalIEEE Magnetics Letters
DOIs
StateAccepted/In press - Nov 29 2017

Keywords

  • Iron
  • Magnetic anisotropy
  • Magnetic films
  • Magnetic Films
  • Magnetic Measurements
  • Nickel
  • Niobium
  • Soft Magnetic Materials
  • Superconducting magnets

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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