Controlling magnetic configuration in soft–hard bilayers probed by polarized neutron reflectometry

Tang, Nan; Liao, Jung-Wei; Chui, Siu-Tat; Ziman, Timothy; Grutter, Alexander J.; Liu, Kai; Lai, Chih-Huang; Kirby, Brian J.; Gilbert, Dustin A.

doi:10.1063/5.0072812

Title: Controlling magnetic configuration in soft–hard bilayers probed by polarized neutron reflectometry

Journal Article · 13 January 2022 · APL Materials

DOI: https://doi.org/10.1063/5.0072812 · OSTI ID:1978985

Tang, Nan ^[1]; Liao, Jung-Wei ^[2];

^[3];

^[4]; Grutter, Alexander J. ^[5];

^[6];

^[7];

^[8]

University of Tennessee, Knoxville, TN (United States); University of Tennessee, Knoxville, Tennessee 37996, USA
University of Cambridge (United Kingdom)
University of Delaware, Newark, DE (United States)
Institut Laue-Langevin, Grenoble (France); Université de Grenobles-Alpes, Grenoble (France)
National Institute of Standards and Technology (NIST), Gaithersburg, MD (United States)
Georgetown University, Washington, DC (United States)
National Tsing Hua University, Hsinchu (Taiwan)
University of Tennessee, Knoxville, TN (United States)

Hard/soft magnetic bilayer thin films have been widely used in data storage technologies and permanent magnet applications. The magnetic configuration and response to temperatures and magnetic fields in these heterostructures are considered to be highly dependent on the interfacial coupling. However, the intrinsic properties of each of the layers, such as the saturation magnetization and layer thickness, also strongly influence the magnetic configuration. Changing these parameters provides an effective method to tailor magnetic properties in composite magnets. Here, we use polarized neutron reflectometry (PNR) to experimentally probe the interfacial magnetic configurations in the hard/soft bilayer thin films: L1₀-FePt/A1-FePt, [Co/Pd]/CoPd, [Co/Pt]/FeNi, and L1₀-FePt/Fe, all of which have a perpendicular magnetic anisotropy in the hard layer. These films were designed with different soft and hard layer thicknesses (t_soft and t_hard) and saturation magnetization (M$$_s^{soft}$$ and M$$_s^{hard}$$). The influences of an in-plane magnetic field (H_ip) and temperature (T) are also studied using a L1₀-FePt/A1-FePt bilayer sample. Comparing the PNR results to the micromagnetic simulations reveals that the interfacial magnetic configuration is highly dependent on t_soft, M$$_s^{soft}, and the external factors (H_ip and T) and has a relatively weak dependence on t_hard and M$$_s^{hard}$. Key among these results, for thin t_soft, the hard and soft layers are rigidly coupled in the out-of-plane direction and then undergo a transition to relax in-plane. This transition can be delayed to larger t_soft by decreasing M$$_s^{soft}$$. Understanding the influence of these parameters on the magnetic configuration is critical to designing functional composite magnets for applications.

View Accepted Manuscript (DOE)

Cite

Export

Save

Research Organization:: University of Tennessee, Knoxville, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

Grant/Contract Number:: SC0021344

OSTI ID:: 1978985

Journal Information:: APL Materials, Journal Name: APL Materials Journal Issue: 1 Vol. 10; ISSN 2166-532X

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

References (50)

Energy Product Enhancement in Imperfectly Exchange-Coupled Nanocomposite Magnets Quesada, Adrian; Granados-Miralles, Cecilia; López-Ortega, Alberto Advanced Electronic Materials, Vol. 2, Issue 4 https://doi.org/10.1002/aelm.201500365	journal	February 2016
Application of polarized neutron reflectometry to studies of artificially structured magnetic materials Zhu, Yimei Modern Techniques for Characterizing Magnetic Materials https://doi.org/10.1007/0-387-23395-4_3	book	January 2005
Phase-sensitive specular neutron reflectometry for imaging the nanometer scale composition depth profile of thin-film materials Kirby, B. J.; Kienzle, P. A.; Maranville, B. B. Current Opinion in Colloid & Interface Science, Vol. 17, Issue 1 https://doi.org/10.1016/j.cocis.2011.11.001	journal	February 2012
Exchange-coupled perpendicular media Suess, D.; Lee, J.; Fidler, J. Journal of Magnetism and Magnetic Materials, Vol. 321, Issue 6 https://doi.org/10.1016/j.jmmm.2008.06.041	journal	March 2009
Giant enhancement of (BH)max in BaFe12O19/Y3Fe5O12 nanocomposite powders Yang, Haibo; Ye, Ting; Lin, Ying Materials Letters, Vol. 145 https://doi.org/10.1016/j.matlet.2015.01.080	journal	April 2015
Recording physics of perpendicular media: soft underlayers Litvinov, Dmitri; Kryder, Mark H.; Khizroev, Sakhrat Journal of Magnetism and Magnetic Materials, Vol. 232, Issue 1-2 https://doi.org/10.1016/s0304-8853(01)00216-5	journal	June 2001
Coupled granular/continuous medium for thermally stable perpendicular magnetic recording Sonobe, Y.; Weller, D.; Ikeda, Y. Journal of Magnetism and Magnetic Materials, Vol. 235, Issue 1-3 https://doi.org/10.1016/s0304-8853(01)00401-2	journal	October 2001
Hard/soft magnetic heterostructures: model exchange-spring magnets Fullerton, Eric E.; Jiang, J. S.; Bader, S. D. Journal of Magnetism and Magnetic Materials, Vol. 200, Issue 1-3 https://doi.org/10.1016/s0304-8853(99)00376-5	journal	October 1999
Exchange-coupled nanocomposite magnets by nanoparticle self-assembly Zeng, Hao; Li, Jing; Liu, J. P. Nature, Vol. 420, Issue 6914, p. 395-398 https://doi.org/10.1038/nature01208	journal	November 2002
Realization of ground-state artificial skyrmion lattices at room temperature Gilbert, Dustin A.; Maranville, Brian B.; Balk, Andrew L. Nature Communications, Vol. 6, Issue 1 https://doi.org/10.1038/ncomms9462	journal	October 2015
Heat-assisted magnetic recording Pan, Liang; Bogy, David B. Nature Photonics, Vol. 3, Issue 4 https://doi.org/10.1038/nphoton.2009.40	journal	April 2009
Magnetic Yoking and Tunable Interactions in FePt-Based Hard/Soft Bilayers Gilbert, Dustin A.; Liao, Jung-Wei; Kirby, Brian J. Scientific Reports, Vol. 6, Issue 1 https://doi.org/10.1038/srep32842	journal	September 2016
Exchange spring media for perpendicular recording Suess, D.; Schrefl, T.; Fähler, S. Applied Physics Letters, Vol. 87, Issue 1 https://doi.org/10.1063/1.1951053	journal	July 2005
Anisotropy dependence of irreversible switching in Fe∕SmCo and FeNi∕FePt exchange spring magnet films Davies, Joseph E.; Hellwig, Olav; Fullerton, Eric E. Applied Physics Letters, Vol. 86, Issue 26 https://doi.org/10.1063/1.1954898	journal	June 2005
Domain wall assisted magnetic recording Dobin, A. Yu.; Richter, H. J. Applied Physics Letters, Vol. 89, Issue 6 https://doi.org/10.1063/1.2335590	journal	August 2006
Multilayer exchange spring media for magnetic recording Suess, D. Applied Physics Letters, Vol. 89, Issue 11 https://doi.org/10.1063/1.2347894	journal	September 2006
Strong coercivity reduction in perpendicular FePt∕Fe bilayers due to hard/soft coupling Casoli, F.; Albertini, F.; Nasi, L. Applied Physics Letters, Vol. 92, Issue 14 https://doi.org/10.1063/1.2905294	journal	April 2008
Thermal stability of ledge-type L10-FePt/Fe exchange-spring nanocomposites for ultrahigh recording densities Goll, D.; Macke, S. Applied Physics Letters, Vol. 93, Issue 15 https://doi.org/10.1063/1.3001589	journal	October 2008
Enhancement of (BH)max in a hard-soft-ferrite nanocomposite using exchange spring mechanism Roy, Debangsu; Kumar, P. S. Anil Journal of Applied Physics, Vol. 106, Issue 7 https://doi.org/10.1063/1.3213341	journal	October 2009
Finite temperature performance of hard-soft composite nanomagnets and its dependence on geometry structure of composites Belemuk, A. M.; Chui, S. T. Journal of Applied Physics, Vol. 113, Issue 4 https://doi.org/10.1063/1.4788703	journal	January 2013
Highly (001)-oriented thin continuous L 1 ₀ FePt film by introducing an FeO _x cap layer Liao, Jung-Wei; Huang, Kuo-Feng; Wang, Liang-Wei Applied Physics Letters, Vol. 102, Issue 6 https://doi.org/10.1063/1.4793189	journal	February 2013
Magnon softening in exchange-coupled hard-soft nanocomposites Belemuk, A. M.; Chui, S. T. Journal of Applied Physics, Vol. 113, Issue 12 https://doi.org/10.1063/1.4797491	journal	March 2013
Tuning magnetic anisotropy in (001) oriented L1 ₀ (Fe _1−x Cu _x ) ₅₅ Pt ₄₅ films Gilbert, Dustin A.; Wang, Liang-Wei; Klemmer, Timothy J. Applied Physics Letters, Vol. 102, Issue 13 https://doi.org/10.1063/1.4799651	journal	April 2013
Tuning perpendicular anisotropy gradient in Co/Pd multilayers by ion irradiation Greene, Peter K.; Osten, Julia; Lenz, Kilian Applied Physics Letters, Vol. 105, Issue 7 https://doi.org/10.1063/1.4893569	journal	August 2014
Probing the A 1 to L 1 ₀ transformation in FeCuPt using the first order reversal curve method Gilbert, Dustin A.; Liao, Jung-Wei; Wang, Liang-Wei APL Materials, Vol. 2, Issue 8 https://doi.org/10.1063/1.4894197	journal	August 2014
Fundamental limits in heat-assisted magnetic recording and methods to overcome it with exchange spring structures Suess, D.; Vogler, C.; Abert, C. Journal of Applied Physics, Vol. 117, Issue 16 https://doi.org/10.1063/1.4918609	journal	April 2015
Interphase exchange effects in CoPt/Co bilayer thin films Lewis, L. H.; Kim, J.; Barmak, K. Journal of Physics D: Applied Physics, Vol. 37, Issue 19 https://doi.org/10.1088/0022-3727/37/19/004	journal	September 2004
Simultaneous enhancement of anisotropy and grain isolation in CoPtCr-SiO 2 perpendicular recording media by a MnRu intermediate layer Liao, Jung-Wei; Dumas, Randy K.; Hou, Hao-Cheng Physical Review B, Vol. 82, Issue 1 https://doi.org/10.1103/PhysRevB.82.014423	journal	July 2010
Exchange-spring behavior in epitaxial hard/soft magnetic bilayers Fullerton, Eric E.; Jiang, J. S.; Grimsditch, M. Physical Review B, Vol. 58, Issue 18 https://doi.org/10.1103/physrevb.58.12193	journal	November 1998
Magnetization reversal of Co ∕ Pt multilayers: Microscopic origin of high-field magnetic irreversibility Davies, Joseph E.; Hellwig, Olav; Fullerton, Eric E. Physical Review B, Vol. 70, Issue 22 https://doi.org/10.1103/physrevb.70.224434	journal	December 2004
Magnetic phase diagram and demagnetization processes in perpendicular exchange-spring multilayers Asti, G.; Ghidini, M.; Pellicelli, R. Physical Review B, Vol. 73, Issue 9 https://doi.org/10.1103/physrevb.73.094406	journal	March 2006
Dependence of exchange coupling interaction on micromagnetic constants in hard/soft magnetic bilayer systems Zambano, A. J.; Oguchi, H.; Takeuchi, I. Physical Review B, Vol. 75, Issue 14 https://doi.org/10.1103/physrevb.75.144429	journal	April 2007
Vertically graded anisotropy in Co/Pd multilayers Kirby, B. J.; Davies, J. E.; Liu, Kai Physical Review B, Vol. 81, Issue 10 https://doi.org/10.1103/physrevb.81.100405	journal	March 2010
Thickness dependence of exchange coupling in epitaxial Fe 3 O 4 / CoFe 2 O 4 soft/hard magnetic bilayers Lavorato, G.; Winkler, E.; Rivas-Murias, B. Physical Review B, Vol. 94, Issue 5 https://doi.org/10.1103/physrevb.94.054405	journal	August 2016
Asymmetric Reversal in Inhomogeneous Magnetic Heterostructures Li, Zhi-Pan; Petracic, Oleg; Morales, Rafael Physical Review Letters, Vol. 96, Issue 21 https://doi.org/10.1103/physrevlett.96.217205	journal	June 2006
The exchange-spring magnet: a new material principle for permanent magnets Kneller, E. F.; Hawig, R. IEEE Transactions on Magnetics, Vol. 27, Issue 4, p. 3588-3560 https://doi.org/10.1109/20.102931	journal	July 1991
Spring magnet films Jiang, J. S.; Fullerton, E. E.; Sowers, C. H. IEEE Transactions on Magnetics, Vol. 35, Issue 5 https://doi.org/10.1109/20.800484	journal	January 1999
Thermal stability and SNR of coupled granular/continuous media Sonobe, Y.; Weller, D.; Ikeda, Y. IEEE Transactions on Magnetics, Vol. 37, Issue 4 https://doi.org/10.1109/20.950932	journal	July 2001
HAMR Areal Density Demonstration of 1+ Tbpsi on Spinstand Wu, Alexander Q.; Kubota, Yukiko; Klemmer, Timothy IEEE Transactions on Magnetics, Vol. 49, Issue 2 https://doi.org/10.1109/TMAG.2012.2219513	journal	February 2013
Heat Assisted Magnetic Recording Kryder, M. H.; Gage, E. C.; McDaniel, T. W. Proceedings of the IEEE, Vol. 96, Issue 11 https://doi.org/10.1109/jproc.2008.2004315	journal	November 2008
Thermally stable CGC perpendicular recording media with Pt-rich CoPtCr and thin Pt layers Sonobe, Y.; Muraoka, H.; Miura, K. IEEE Transactions on Magnetics, Vol. 38, Issue 5 https://doi.org/10.1109/tmag.2002.801810	journal	September 2002
Exchange coupled composite media for perpendicular magnetic recording Victora, R. H.; Shen, X. IEEE Transactions on Magnetics, Vol. 41, Issue 10 https://doi.org/10.1109/tmag.2005.855263	journal	October 2005
Exchange coupled composite media for perpendicular magnetic recording IEEE Transactions on Magnetics, Vol. 41, Issue 10 https://doi.org/10.1109/tmag.2005.855278	journal	October 2005
Perpendicular recording CoPtCrO composite media with performance enhancement capping layer Choe, G.; Zheng, M.; Acharya, B. R. IEEE Transactions on Magnetics, Vol. 41, Issue 10 https://doi.org/10.1109/tmag.2005.855283	journal	October 2005
Heat-Assisted Magnetic Recording Rottmayer, R. E.; Batra, S.; Buechel, D. IEEE Transactions on Magnetics, Vol. 42, Issue 10 https://doi.org/10.1109/tmag.2006.879572	journal	October 2006
Future Options for HDD Storage Shiroishi, Y.; Fukuda, K.; Tagawa, I. IEEE Transactions on Magnetics, Vol. 45, Issue 10 https://doi.org/10.1109/tmag.2009.2024879	journal	October 2009
L1$_{0}$-Ordered FePt-Based Perpendicular Magnetic Recording Media for Heat-Assisted Magnetic Recording Varaprasad, B. S. D. Ch. S.; Chen, M.; Takahashi, Y. K. IEEE Transactions on Magnetics, Vol. 49, Issue 2 https://doi.org/10.1109/tmag.2012.2218227	journal	February 2013
Review Article: FePt heat assisted magnetic recording media Weller, Dieter; Parker, Gregory; Mosendz, Oleksandr Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, Vol. 34, Issue 6 https://doi.org/10.1116/1.4965980	journal	November 2016
Materials for heat-assisted magnetic recording Kief, M. T.; Victora, R. H. MRS Bulletin, Vol. 43, Issue 2 https://doi.org/10.1557/mrs.2018.2	journal	February 2018
OOMMF User's Guide, Version 1.0 Donahue, M. J.; Porter, D. G. National Institute of Standards and Technology (NIST) https://doi.org/10.6028/NIST.IR.6376	report	September 1999

Similar Records

Hard/graded exchange spring composite media based on FePt

Journal Article · 2011 · Journal of Applied Physics · OSTI ID:21560103

Alexandrakis, V; Speliotis, Th; Manios, E; +4 more

Domain wall assisted magnetization switching in (111) oriented L1{sub 0} FePt grown on a soft magnetic metallic glass

Journal Article · 2010 · Applied Physics Letters · OSTI ID:21466897

Kaushik, Neelam; Sharma, Parmanand; Yubuta, Kunio; +2 more

Structural and magnetic properties of L1(0)/A1, FePt nanocomposites

Journal Article · 2013 · Journal of Magnetism and Magnetic Materials · OSTI ID:1211061

Giannopoulos, G; Speliotis, T; Li, WF; +2 more

Related Subjects

36 MATERIALS SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
data storage and retrieval
depth profiling techniques
exchange interactions
heterostructures
magnetic anisotropy
magnetic materials
magnetic ordering
neutron reflectometry
thin films

Title: Controlling magnetic configuration in soft–hard bilayers probed by polarized neutron reflectometry

Citation Formats

References (50)

Similar Records

Related Subjects