Reduction and change of magnetic properties of Co(OH)2 on milling with Al

T. Kamei, Tetsuhiko Isobe, M. Senna, T. Shinohara, F. Wagatsuma, K. Sumiyama, K. Suzuki

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The reduction process and change of the magnetic properties have been investigated for a mixture comprising Co(OH)2 and metallic Al as a function of mechanical milling. Dehydration and apparent thermit reaction by milling are detected by thermal analyses (TGDTA). With increasing the milling time, the magnetization, M, becomes temperature-independent above 50K, whereas M at 5K rapidly decreases. At above 100K, M shows a maximum after milling for12h due to reduction to form metallic Co. Zero-field 59Co-spin echo NMR signals are detected for the milled mixture. Marked negative Knight shift of 27Al NMR by milling is induced by the polarization of 3d spins of neighboring Co atoms. At the later stage of milling partial re-oxidation of Co and compounding with aluminum takes place. The neighboring structure of cobalt atoms is widely distributed, as confirmed by the separate 59Co NMR signals.

Original languageEnglish
Pages (from-to)247-252
Number of pages6
JournalMaterials Science Forum
Volume269-272
Issue numberPART 1
Publication statusPublished - 1998

Fingerprint

Magnetic properties
Nuclear magnetic resonance
magnetic properties
Atoms
nuclear magnetic resonance
Cobalt
Aluminum
Dehydration
Magnetization
Polarization
compounding
Oxidation
dehydration
atoms
echoes
cobalt
aluminum
Temperature
magnetization
oxidation

Keywords

  • Charge transfer
  • Knight shift
  • Mechanical alloying Al-Co(OH)
  • Zero-field NMR

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Kamei, T., Isobe, T., Senna, M., Shinohara, T., Wagatsuma, F., Sumiyama, K., & Suzuki, K. (1998). Reduction and change of magnetic properties of Co(OH)2 on milling with Al. Materials Science Forum, 269-272(PART 1), 247-252.

Reduction and change of magnetic properties of Co(OH)2 on milling with Al. / Kamei, T.; Isobe, Tetsuhiko; Senna, M.; Shinohara, T.; Wagatsuma, F.; Sumiyama, K.; Suzuki, K.

In: Materials Science Forum, Vol. 269-272, No. PART 1, 1998, p. 247-252.

Research output: Contribution to journalArticle

Kamei, T, Isobe, T, Senna, M, Shinohara, T, Wagatsuma, F, Sumiyama, K & Suzuki, K 1998, 'Reduction and change of magnetic properties of Co(OH)2 on milling with Al', Materials Science Forum, vol. 269-272, no. PART 1, pp. 247-252.
Kamei T, Isobe T, Senna M, Shinohara T, Wagatsuma F, Sumiyama K et al. Reduction and change of magnetic properties of Co(OH)2 on milling with Al. Materials Science Forum. 1998;269-272(PART 1):247-252.
Kamei, T. ; Isobe, Tetsuhiko ; Senna, M. ; Shinohara, T. ; Wagatsuma, F. ; Sumiyama, K. ; Suzuki, K. / Reduction and change of magnetic properties of Co(OH)2 on milling with Al. In: Materials Science Forum. 1998 ; Vol. 269-272, No. PART 1. pp. 247-252.
@article{6f59d885b4f6496cad348c677582678b,
title = "Reduction and change of magnetic properties of Co(OH)2 on milling with Al",
abstract = "The reduction process and change of the magnetic properties have been investigated for a mixture comprising Co(OH)2 and metallic Al as a function of mechanical milling. Dehydration and apparent thermit reaction by milling are detected by thermal analyses (TGDTA). With increasing the milling time, the magnetization, M, becomes temperature-independent above 50K, whereas M at 5K rapidly decreases. At above 100K, M shows a maximum after milling for12h due to reduction to form metallic Co. Zero-field 59Co-spin echo NMR signals are detected for the milled mixture. Marked negative Knight shift of 27Al NMR by milling is induced by the polarization of 3d spins of neighboring Co atoms. At the later stage of milling partial re-oxidation of Co and compounding with aluminum takes place. The neighboring structure of cobalt atoms is widely distributed, as confirmed by the separate 59Co NMR signals.",
keywords = "Charge transfer, Knight shift, Mechanical alloying Al-Co(OH), Zero-field NMR",
author = "T. Kamei and Tetsuhiko Isobe and M. Senna and T. Shinohara and F. Wagatsuma and K. Sumiyama and K. Suzuki",
year = "1998",
language = "English",
volume = "269-272",
pages = "247--252",
journal = "Materials Science Forum",
issn = "0255-5476",
publisher = "Trans Tech Publications",
number = "PART 1",

}

TY - JOUR

T1 - Reduction and change of magnetic properties of Co(OH)2 on milling with Al

AU - Kamei, T.

AU - Isobe, Tetsuhiko

AU - Senna, M.

AU - Shinohara, T.

AU - Wagatsuma, F.

AU - Sumiyama, K.

AU - Suzuki, K.

PY - 1998

Y1 - 1998

N2 - The reduction process and change of the magnetic properties have been investigated for a mixture comprising Co(OH)2 and metallic Al as a function of mechanical milling. Dehydration and apparent thermit reaction by milling are detected by thermal analyses (TGDTA). With increasing the milling time, the magnetization, M, becomes temperature-independent above 50K, whereas M at 5K rapidly decreases. At above 100K, M shows a maximum after milling for12h due to reduction to form metallic Co. Zero-field 59Co-spin echo NMR signals are detected for the milled mixture. Marked negative Knight shift of 27Al NMR by milling is induced by the polarization of 3d spins of neighboring Co atoms. At the later stage of milling partial re-oxidation of Co and compounding with aluminum takes place. The neighboring structure of cobalt atoms is widely distributed, as confirmed by the separate 59Co NMR signals.

AB - The reduction process and change of the magnetic properties have been investigated for a mixture comprising Co(OH)2 and metallic Al as a function of mechanical milling. Dehydration and apparent thermit reaction by milling are detected by thermal analyses (TGDTA). With increasing the milling time, the magnetization, M, becomes temperature-independent above 50K, whereas M at 5K rapidly decreases. At above 100K, M shows a maximum after milling for12h due to reduction to form metallic Co. Zero-field 59Co-spin echo NMR signals are detected for the milled mixture. Marked negative Knight shift of 27Al NMR by milling is induced by the polarization of 3d spins of neighboring Co atoms. At the later stage of milling partial re-oxidation of Co and compounding with aluminum takes place. The neighboring structure of cobalt atoms is widely distributed, as confirmed by the separate 59Co NMR signals.

KW - Charge transfer

KW - Knight shift

KW - Mechanical alloying Al-Co(OH)

KW - Zero-field NMR

UR - http://www.scopus.com/inward/record.url?scp=0009436078&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0009436078&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0009436078

VL - 269-272

SP - 247

EP - 252

JO - Materials Science Forum

JF - Materials Science Forum

SN - 0255-5476

IS - PART 1

ER -