skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

Abstract

Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.

Authors:
; ; ; ; ; ;  [1]; ;  [2]; ;  [3]; ; ;  [4];  [3];  [5]
  1. Department of Engineering Sciences, Uppsala University, 75121 Uppsala (Sweden)
  2. Department of Physics, University of Colorado, Colorado Springs, Colorado 80918 (United States)
  3. Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden)
  4. Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden)
  5. (Sweden)
Publication Date:
OSTI Identifier:
22415195
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COPPER; COUPLING CONSTANTS; FERROMAGNETIC RESONANCE; HYSTERESIS; IRON; LAYERS; NICKEL; SILICA; SILICON OXIDES; SIMULATION; STRONG-COUPLING MODEL; SUBSTRATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Wei, Yajun, E-mail: yajun.wei@angstrom.uu.se, Akansel, Serkan, Thersleff, Thomas, Brucas, Rimantas, Lansaker, Pia, Leifer, Klaus, Svedlindh, Peter, Harward, Ian, Celinski, Zbigniew, Ranjbar, Mojtaba, Dumas, Randy K., Jana, Somnath, Pogoryelov, Yevgen, Karis, Olof, Åkerman, Johan, and Department of Applied Physics and Microelectronics, Royal Institute of Technology, 10044 Kista. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers. United States: N. p., 2015. Web. doi:10.1063/1.4906591.
Wei, Yajun, E-mail: yajun.wei@angstrom.uu.se, Akansel, Serkan, Thersleff, Thomas, Brucas, Rimantas, Lansaker, Pia, Leifer, Klaus, Svedlindh, Peter, Harward, Ian, Celinski, Zbigniew, Ranjbar, Mojtaba, Dumas, Randy K., Jana, Somnath, Pogoryelov, Yevgen, Karis, Olof, Åkerman, Johan, & Department of Applied Physics and Microelectronics, Royal Institute of Technology, 10044 Kista. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers. United States. doi:10.1063/1.4906591.
Wei, Yajun, E-mail: yajun.wei@angstrom.uu.se, Akansel, Serkan, Thersleff, Thomas, Brucas, Rimantas, Lansaker, Pia, Leifer, Klaus, Svedlindh, Peter, Harward, Ian, Celinski, Zbigniew, Ranjbar, Mojtaba, Dumas, Randy K., Jana, Somnath, Pogoryelov, Yevgen, Karis, Olof, Åkerman, Johan, and Department of Applied Physics and Microelectronics, Royal Institute of Technology, 10044 Kista. Mon . "Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers". United States. doi:10.1063/1.4906591.
@article{osti_22415195,
title = {Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers},
author = {Wei, Yajun, E-mail: yajun.wei@angstrom.uu.se and Akansel, Serkan and Thersleff, Thomas and Brucas, Rimantas and Lansaker, Pia and Leifer, Klaus and Svedlindh, Peter and Harward, Ian and Celinski, Zbigniew and Ranjbar, Mojtaba and Dumas, Randy K. and Jana, Somnath and Pogoryelov, Yevgen and Karis, Olof and Åkerman, Johan and Department of Applied Physics and Microelectronics, Royal Institute of Technology, 10044 Kista},
abstractNote = {Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.},
doi = {10.1063/1.4906591},
journal = {Applied Physics Letters},
number = 4,
volume = 106,
place = {United States},
year = {Mon Jan 26 00:00:00 EST 2015},
month = {Mon Jan 26 00:00:00 EST 2015}
}
  • We investigated the magnetic interlayer coupling between two ferromagnetic (FM) Ni layers through an antiferromagnetic (AFM) Ni{sub 25}Mn{sub 75} layer and the influence of this coupling on the exchange bias phenomenon. The interlayer coupling energy of an epitaxial trilayer of 14 atomic monolayers (ML) Ni/45 ML Ni{sub 25}Mn{sub 75}/16 ML Ni on Cu{sub 3}Au(001) was extracted from minor-loop magnetization measurements using in-situ magneto-optical Kerr effect. The interlayer coupling changes from ferromagnetic to antiferromagnetic when the temperature is increased above 300 K. This sign change is interpreted as the result of the competition between an antiparallel Ruderman-Kittel-Kasuya-Yosida (RKKY)-type interlayer coupling, which dominatesmore » at high temperature, and a stronger direct exchange coupling across the AFM layer, which is present only below the Néel temperature of the AFM layer.« less
  • Magnetic properties of sputtered NiFe/IrMn/Co trilayers grown on different seed layers (Cu or Ta) deposited on Si (100) substrates were investigated by magnetometry and ferromagnetic resonance measurements. Exchange bias effect and magnetic spring behavior have been studied by changing the IrMn thickness. As shown by X-ray diffraction, Ta and Cu seed layers provoke different degrees of (111) fcc-texture that directly affect the exchange bias and indirectly modify the exchange spring coupling behavior. Increasing the IrMn thickness, it was observed that the coupling angle between the Co and NiFe ferromagnetic layers increases for the Cu seed system, but it reduces formore » the Ta case. The results were explained considering (i) different anisotropies of the Co and IrMn layers induced by the different degree of the (111) texture and (ii) the distinct exchange bias set at the NiFe/IrMn and IrMn/Co interfaces in both systems. The NiFe and Co interlayer coupling angle is strongly correlated with both exchange bias and exchange magnetic spring phenomena. It was also shown that the highest exchange bias field occurs when an unstressed L1{sub 2} IrMn structure is stabilized.« less
  • The strain mediated electrical and magnetic properties were investigated in PZT/Ni-Mn-In heterostructure deposited on Si (100) by dc/rf magnetron sputtering. X-ray diffraction pattern revealed that (220) orientation of Ni-Mn-In facilitate the (110) oriented tertragonal phase growth of PZT layer in PZT/Ni-Mn-In heterostructure. A distinctive peak in dielectric constant versus temperature plots around martensitic phase transformation temperature of Ni-Mn-In showed a strain mediated coupling between Ni-Mn-In and PZT layers. The ferroelectric measurement taken at different temperatures exhibits a well saturated and temperature dependent P-E loops with a highest value of P{sub sat}~55 μC/cm² obtained during martensite-austenite transition temperature region of Ni-Mn-In.more » The stress induced by Ni-Mn-In layer on upper PZT film due to structural transformation from martensite to austenite resulted in temperature modulated Tunability of PZT/Ni-Mn-In heterostructure. A tunability of 42% was achieved at 290 K (structural transition region of Ni-Mn-In) in these heterostructures. I-V measurements taken at different temperatures indicated that ohmic conduction was the main conduction mechanism over a large electric field range in these heterostructures. Magnetic measurement revealed that heterostructure was ferromagnetic at room temperature with a saturation magnetization of ~123 emu/cm³. Such multiferroic heterostructures exhibits promising applications in various microelectromechanical systems.« less
  • A dc superconducting quantum interference device (SQUID) is fabricated on an amorphous Y-Ba-Cu-O film by a photolithographic technique and successive post-annealing treatment. The SQUID shows periodic and symmetric behavior in the voltage versus magnetic-flux curves ({ital V}-{Phi} curves). No multiple periodicities are observed. The transfer function {partial derivative}{ital V}/{partial derivative}{Phi} for output voltage is about 90 and 20 {mu}V/{Phi}{sub 0} at 4.2 and 56 K, respectively. It is expected that the SQUID contains only two symmetric active Josephson junctions.