Metallic 10 nm diameter magnetic sensors and large-scale ordered arrays

Sang Yeob Sung, Mazin M. Maqableh, Xiaobo Huang, K. Sai Madhukar Reddy, R. H. Victora, Bethanie J.H. Stadler

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Metallic nanowires with low resistivity were grown inside insulating aluminum oxide matrices that contained very uniform columnar nanopores (10.6+/1.7 nm diameters). These nanopores can be made with large-scale order (cm2), which is desirable in applications such as hard drive read sensors and random access memories. The nanowires are grown by electrochemical deposition directly inside the alumina to avoid sidewall damage compared to nanostructures that are defined from films by lithographical patterning and etching. Specifically, trilayers of [Co(15 nm)/Cu(5 nm)/Co(10 nm)] were synthesized and measured to have 30 (Ω) resistance and 19% magnetoresistance. These parameters are desirable for read head sensors, especially because the nanowires described here have 1:1 aspect ratios, and (10×) smaller areas and (100×) lower resistances than conventional read sensors based on lithographically produced magnetic tunnel junctions. A new nanostamping technique is introduced, in which linear stamps with ordered cm2) areas are imprinted onto aluminum precursors to produce ordered nanoporous aluminum oxide upon anodization. These stamps are substantially less-time consuming and cheaper to make than dot type stamps, and the order enables closely spaced arrays of CPP-GMR sensors for one-pass 2-D recording and cross recording. Importantly, the GMR sensors are grown directly into aluminum oxide with 20 nm separation. Therefore, a relatively large pattern (30 × 100 nm) can be used to produce three 10 nm-diameter GMR sensors without roughening or redeposition on sidewalls. The sensors are also already embedded in alumina for subsequent device processing.

Original languageEnglish (US)
Article number6971786
JournalIEEE Transactions on Magnetics
Volume50
Issue number11
DOIs
StatePublished - Nov 1 2014

Keywords

  • 2-D recording
  • CPP-GMR
  • cross recording (CR)
  • nanoimprinting
  • read sensor arrays

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