Related Experiment Video
Updated: Jun 3, 2026
06:34
Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites
Published on: September 19, 2020
Interlayer exchange coupling effect of L1(0) CoPt based exchange coupled composite media.
Yang Yang1, K K M Pandey, J S Chen
1Department of Materials Science and Engineering, National University of Singapore, 119260, Republic of Singapore.
Journal of Nanoscience and Nanotechnology
|April 1, 2011
Summary
The thickness of the soft magnetic layer significantly impacts magnetic media performance. Thinner soft layers (4 nm and below) effectively reduce switching fields and improve magnetization reversal behavior in CoPt-SiO2 composite media.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Exchange-coupled composite (ECC) media are crucial for high-density magnetic recording.
- Understanding the influence of soft magnetic layer thickness is vital for optimizing ECC media performance.
Purpose of the Study:
- To investigate the effect of soft magnetic layer thickness on the switching field and magnetization reversal behavior of CoPt-SiO2(soft)/CoPt-SiO2(hard) exchange-coupled media.
Main Methods:
- Fabrication of CoPt-SiO2(soft)/CoPt-SiO2(hard) exchange-coupled media with varying soft layer thicknesses.
- Characterization of magnetic properties including coercivity, magnetization squareness, and switching field.
Main Results:
- Increasing soft layer thickness decreased coercivity and magnetization squareness.
- Soft layer thickness of 4 nm and below significantly reduced the switching field compared to thicker layers.
- Increased soft layer thickness led to more incoherent magnetization reversal behavior.
Conclusions:
- Soft layer thickness is a critical parameter for controlling the magnetic properties of CoPt-SiO2 ECC media.
- Optimizing soft layer thickness below 4 nm is essential for achieving reduced switching fields and desired reversal characteristics.
More Related Videos
Related Concept Videos
01:08NMR Spectroscopy: Spin–Spin Coupling
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...
01:27¹H NMR: Long-Range Coupling
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
01:17Ion Exchange
Ion exchange chromatography separates charged molecules from a solution by reversibly exchanging them with mobile, or 'active', ions associated with the oppositely charged stationary phase. This method can be used to separate ions, soften and deionize water, and purify solutions. The polymers comprising the ion-exchange column are high-molecular-weight and chemically stable polymers, crosslinked to be porous and essentially insoluble. They are also functionalized with either acidic or basic...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:20Convolution Properties I
Convolution computations can be simplified by utilizing their inherent properties.
The commutative property reveals that the input and the impulse response of an LTI (Linear Time-Invariant) system can be interchanged without affecting the output:
The commutative property reveals that the input and the impulse response of an LTI (Linear Time-Invariant) system can be interchanged without affecting the output:
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...