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

Fuente: arXiv
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Main Authors: Tang, Nan, Liao, Jung-Wei, Chui, Siu-Tat, Ziman, Timothy, Lai, Kai Liu6 Chih-Huang, Kirby, Brian J., Gilbert, Dustin A.
Format: Preprint
Published: 2021
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author Tang, Nan
Liao, Jung-Wei
Chui, Siu-Tat
Ziman, Timothy
Lai, Kai Liu6 Chih-Huang
Kirby, Brian J.
Gilbert, Dustin A.
author_facet Tang, Nan
Liao, Jung-Wei
Chui, Siu-Tat
Ziman, Timothy
Lai, Kai Liu6 Chih-Huang
Kirby, Brian J.
Gilbert, Dustin A.
contents 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 hard/soft bilayer thin films: L10-FePt/A1-FePt, [Co/Pd] /CoPd, [Co/Pt] /FeNi and L10-FePt/Fe, which all 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), respectively. 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 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, 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.
format Preprint
id arxiv_https___arxiv_org_abs_2111_12191
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Controlling magnetic configuration in soft-hard bilayers probed by polarized neutron reflectometry
Tang, Nan
Liao, Jung-Wei
Chui, Siu-Tat
Ziman, Timothy
Lai, Kai Liu6 Chih-Huang
Kirby, Brian J.
Gilbert, Dustin A.
Materials Science
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 hard/soft bilayer thin films: L10-FePt/A1-FePt, [Co/Pd] /CoPd, [Co/Pt] /FeNi and L10-FePt/Fe, which all 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), respectively. 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 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, 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.
title Controlling magnetic configuration in soft-hard bilayers probed by polarized neutron reflectometry
topic Materials Science
url https://arxiv.org/abs/2111.12191