Annealing effects on tunnel magnetoresistance in polyimide-Co granular films

Kazuya Z. Suzuki; Yuma Shibuya; Tomohiko Niizeki; Hideto Yanagihara; Eiji Kita

doi:10.1109/TMAG.2013.2274725

Annealing effects on tunnel magnetoresistance in polyimide-Co granular films

Kazuya Z. Suzuki, Yuma Shibuya, Tomohiko Niizeki, Hideto Yanagihara, Eiji Kita

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Recently, we reported on the synthesis of a high-quality polyimide-Co (PI-Co) granular thin film using vapor deposition polymerization. This thin film had a tunnel magnetoresistance (TMR) ratio of 2.6% at room temperature. Because thermal annealing is considered effective for manipulating the grain size in granular systems composed ofmetallic ferromagnetic grains sampleswere annealed at temperatures between 473 K and 673 K in high vacuum. All samples were superparamagnetic at room temperature, and the average diameter of the Co particles, as deduced from Langevin analysis, increased significantly in the sample annealed at 623 K. The temperature dependence of the electrical resistance indicated tunneling conduction between Co particles in all samples. The TMR ratio increased to 4.8% at an annealing temperature of 473 K but decreased significantly after annealing above 623 K. This change was attributed to PI decomposition, as determined from the IR spectra.

Original language	English
Article number	2274725
Journal	IEEE Transactions on Magnetics
Volume	50
Issue number	1
DOIs	https://doi.org/10.1109/TMAG.2013.2274725
Publication status	Published - 2014 Jan

Keywords

Co particle
Granular film
Polyimide (PI)
Tunnel magnetoresistance (TMR)
Vapor deposition polymerization

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

Access to Document

10.1109/TMAG.2013.2274725

Cite this

@article{ea57c015feba47f19b6cecf33d5657f5,

title = "Annealing effects on tunnel magnetoresistance in polyimide-Co granular films",

abstract = "Recently, we reported on the synthesis of a high-quality polyimide-Co (PI-Co) granular thin film using vapor deposition polymerization. This thin film had a tunnel magnetoresistance (TMR) ratio of 2.6% at room temperature. Because thermal annealing is considered effective for manipulating the grain size in granular systems composed ofmetallic ferromagnetic grains sampleswere annealed at temperatures between 473 K and 673 K in high vacuum. All samples were superparamagnetic at room temperature, and the average diameter of the Co particles, as deduced from Langevin analysis, increased significantly in the sample annealed at 623 K. The temperature dependence of the electrical resistance indicated tunneling conduction between Co particles in all samples. The TMR ratio increased to 4.8% at an annealing temperature of 473 K but decreased significantly after annealing above 623 K. This change was attributed to PI decomposition, as determined from the IR spectra.",

keywords = "Co particle, Granular film, Polyimide (PI), Tunnel magnetoresistance (TMR), Vapor deposition polymerization",

author = "Suzuki, {Kazuya Z.} and Yuma Shibuya and Tomohiko Niizeki and Hideto Yanagihara and Eiji Kita",

year = "2014",

month = jan,

doi = "10.1109/TMAG.2013.2274725",

language = "English",

volume = "50",

journal = "IEEE Transactions on Magnetics",

issn = "0018-9464",

publisher = "Institute of Electrical and Electronics Engineers Inc.",

number = "1",

}

TY - JOUR

T1 - Annealing effects on tunnel magnetoresistance in polyimide-Co granular films

AU - Suzuki, Kazuya Z.

AU - Shibuya, Yuma

AU - Niizeki, Tomohiko

AU - Yanagihara, Hideto

AU - Kita, Eiji

PY - 2014/1

Y1 - 2014/1

N2 - Recently, we reported on the synthesis of a high-quality polyimide-Co (PI-Co) granular thin film using vapor deposition polymerization. This thin film had a tunnel magnetoresistance (TMR) ratio of 2.6% at room temperature. Because thermal annealing is considered effective for manipulating the grain size in granular systems composed ofmetallic ferromagnetic grains sampleswere annealed at temperatures between 473 K and 673 K in high vacuum. All samples were superparamagnetic at room temperature, and the average diameter of the Co particles, as deduced from Langevin analysis, increased significantly in the sample annealed at 623 K. The temperature dependence of the electrical resistance indicated tunneling conduction between Co particles in all samples. The TMR ratio increased to 4.8% at an annealing temperature of 473 K but decreased significantly after annealing above 623 K. This change was attributed to PI decomposition, as determined from the IR spectra.

AB - Recently, we reported on the synthesis of a high-quality polyimide-Co (PI-Co) granular thin film using vapor deposition polymerization. This thin film had a tunnel magnetoresistance (TMR) ratio of 2.6% at room temperature. Because thermal annealing is considered effective for manipulating the grain size in granular systems composed ofmetallic ferromagnetic grains sampleswere annealed at temperatures between 473 K and 673 K in high vacuum. All samples were superparamagnetic at room temperature, and the average diameter of the Co particles, as deduced from Langevin analysis, increased significantly in the sample annealed at 623 K. The temperature dependence of the electrical resistance indicated tunneling conduction between Co particles in all samples. The TMR ratio increased to 4.8% at an annealing temperature of 473 K but decreased significantly after annealing above 623 K. This change was attributed to PI decomposition, as determined from the IR spectra.

KW - Co particle

KW - Granular film

KW - Polyimide (PI)

KW - Tunnel magnetoresistance (TMR)

KW - Vapor deposition polymerization

UR - http://www.scopus.com/inward/record.url?scp=84904318002&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84904318002&partnerID=8YFLogxK

U2 - 10.1109/TMAG.2013.2274725

DO - 10.1109/TMAG.2013.2274725

M3 - Article

AN - SCOPUS:84904318002

VL - 50

JO - IEEE Transactions on Magnetics

JF - IEEE Transactions on Magnetics

SN - 0018-9464

IS - 1

M1 - 2274725

ER -

Annealing effects on tunnel magnetoresistance in polyimide-Co granular films

Abstract

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this