Interplay between out-of-plane anisotropic L1{sub 1}-type CoPt and in-plane anisotropic NiFe layers in CoPt/NiFe exchange springs

Journal Article · Sat Jun 28 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4885452· OSTI ID:22304493

Saravanan, P. ^[1]; Hsu, Jen-Hwa; Tsai, C. L. ^[1]; Tsai, C. Y.; Lin, Y. H. ^[2]; Kuo, C. Y.; Wu, J. -C. ^[3]; Lee, C. -M. ^[4]

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1. Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)
2. Graduate Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China)
3. Department of Physics, National Chang Hua University of Education, Chang Hua 50000, Taiwan (China)
4. Graduate School of Materials Science, National Yunlin University of Science and Technology, Douliou 64002, Taiwan (China)

Films of L1{sub 1}-type CoPt/NiFe exchange springs were grown with different NiFe (Permalloy) layer thickness (t{sub NiFe} = 0–10 nm). X-ray diffraction analysis reveals that the characteristic peak position of NiFe(111) is not affected by the CoPt-layer—confirming the absence of any inter-diffusion between the CoPt and NiFe layers. Magnetic studies indicate that the magnetization orientation of NiFe layer can be tuned through varying t{sub NiFe} and the perpendicular magnetic anisotropy of L1{sub 1}-type CoPt/NiFe films cannot sustain for t{sub NiFe} larger than 3.0 nm due to the existence of exchange interaction at the interface of L1{sub 1}-CoPt and NiFe layers. Magnetic force microscopy analysis on the as-grown samples shows the changes in morphology from maze-like domains with good contrast to hazy domains when t{sub NiFe} ≥ 3.0 nm. The three-dimensional micro-magnetic simulation results demonstrate that the magnetization orientation in NiFe layer is not uniform, which continuously increases from the interface to the top of NiFe layer. Furthermore, the tilt angle of the topmost NiFe layers can be changed over a very wide range from a small number to about 75° by varying t{sub NiFe} from 1 to 10 nm. It is worth noting that there is an abrupt change in the magnetization direction at the interface, for all the t{sub NiFe} investigated. The results of present study demonstrate that the tunable tilted exchange springs can be realized with L1{sub 1}-type CoPt/NiFe bilayers for future applications in three-axis magnetic sensors or advanced spintronic devices demanding inclined magnetic anisotropy.

• OSTI ID: 22304493
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
ATOMIC FORCE MICROSCOPY
BINARY ALLOY SYSTEMS
COBALT ALLOYS
DIFFUSION
EXCHANGE INTERACTIONS
FILMS
INTERFACES
IRON ALLOYS
LAYERS
MAGNETIC FIELDS
MAGNETIZATION
NICKEL ALLOYS
PERMALLOY
PLATINUM ALLOYS
SENSORS
SIMULATION
X-RAY DIFFRACTION