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Title: Modifying exchange-spring behavior of CoPt/NiFe bilayer by inserting a Pt or Ru spacer

Abstract

We herein explore the possibility of obtaining tunable tilted magnetic anisotropy in ordered-CoPt (5 nm)/NiFe(t{sub NiFe}) bilayers through modifying their exchange spring behavior by inserting Pt and Ru-spacers. The tuning process of tilt angle magnetization of NiFe-layer was systematically investigated by varying the Pt or Ru thickness (t{sub Pt} or t{sub Ru}) from 0 to 8 nm at different thicknesses of NiFe (t{sub NiFe} = 1.5, 4.0, and 6.0 nm). Polar magneto-optic Kerr effect (p-MOKE) studies reveal that the bilayers grown in absence of spacers exhibit almost a rectangular hysteresis loop. With the insertion of Pt-spacer, the loop becomes more and more tilted as t{sub Pt} increases; whereas, in the case of Ru-spacer, the nature of the loops is not simply changing in one direction. The estimated SQR{sub ⊥} (= θ{sub r}/θ{sub s}) values from the p-MOKE loops are found to monotonically decrease with increasing t{sub Pt} when t{sub Pt} ≦ 4 nm. In contrast, in the case of Ru-spacer, an oscillatory behavior for the SQR{sub ⊥} values is apparent when t{sub Ru} ≦ 4 nm. As a result, an oscillatory tilted angle of NiFe spin configuration was obtained in the case of Ru-spacer; while a decoupling effect was prominent for the Pt-spacer. The results of present studymore » reveal that the insertion of Pt and Ru-spacers as an appropriate means for realizing tunable tilted magnetic anisotropy in the CoPt/NiFe exchange springs.« less

Authors:
;  [1];  [2];  [3]
  1. Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)
  2. Graduate School of Materials Science, National Yunlin University of Science and Technology, Douliou 64002, Taiwan (China)
  3. Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)
Publication Date:
OSTI Identifier:
22409921
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; COBALT; DECOUPLING; HYSTERESIS; INTERMETALLIC COMPOUNDS; IRON; KERR EFFECT; LAYERS; MAGNETIZATION; NICKEL; PLATINUM; SPACERS; SPIN; THICKNESS; THIN FILMS

Citation Formats

Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw, Tsai, C. L., Lee, C.-M., and Saravanan, P. Modifying exchange-spring behavior of CoPt/NiFe bilayer by inserting a Pt or Ru spacer. United States: N. p., 2015. Web. doi:10.1063/1.4913641.
Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw, Tsai, C. L., Lee, C.-M., & Saravanan, P. Modifying exchange-spring behavior of CoPt/NiFe bilayer by inserting a Pt or Ru spacer. United States. doi:10.1063/1.4913641.
Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw, Tsai, C. L., Lee, C.-M., and Saravanan, P. Thu . "Modifying exchange-spring behavior of CoPt/NiFe bilayer by inserting a Pt or Ru spacer". United States. doi:10.1063/1.4913641.
@article{osti_22409921,
title = {Modifying exchange-spring behavior of CoPt/NiFe bilayer by inserting a Pt or Ru spacer},
author = {Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw and Tsai, C. L. and Lee, C.-M. and Saravanan, P.},
abstractNote = {We herein explore the possibility of obtaining tunable tilted magnetic anisotropy in ordered-CoPt (5 nm)/NiFe(t{sub NiFe}) bilayers through modifying their exchange spring behavior by inserting Pt and Ru-spacers. The tuning process of tilt angle magnetization of NiFe-layer was systematically investigated by varying the Pt or Ru thickness (t{sub Pt} or t{sub Ru}) from 0 to 8 nm at different thicknesses of NiFe (t{sub NiFe} = 1.5, 4.0, and 6.0 nm). Polar magneto-optic Kerr effect (p-MOKE) studies reveal that the bilayers grown in absence of spacers exhibit almost a rectangular hysteresis loop. With the insertion of Pt-spacer, the loop becomes more and more tilted as t{sub Pt} increases; whereas, in the case of Ru-spacer, the nature of the loops is not simply changing in one direction. The estimated SQR{sub ⊥} (= θ{sub r}/θ{sub s}) values from the p-MOKE loops are found to monotonically decrease with increasing t{sub Pt} when t{sub Pt} ≦ 4 nm. In contrast, in the case of Ru-spacer, an oscillatory behavior for the SQR{sub ⊥} values is apparent when t{sub Ru} ≦ 4 nm. As a result, an oscillatory tilted angle of NiFe spin configuration was obtained in the case of Ru-spacer; while a decoupling effect was prominent for the Pt-spacer. The results of present study reveal that the insertion of Pt and Ru-spacers as an appropriate means for realizing tunable tilted magnetic anisotropy in the CoPt/NiFe exchange springs.},
doi = {10.1063/1.4913641},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}