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Title: Magnetic hardening studies in sintered Sm(Co,Cu{sub x},Fe,Zr){sub z} 2:17 high temperature magnets

Abstract

Lorentz microscopy combined with conventional transmission electron microscopy were used to image the magnetic domains and microstructures of sintered Sm(Co{sub bal}Cu{sub x}Fe{sub 0.06}Zr{sub 0.03}){sub z} (0.088{<=}x{<=}0.128; 5.8{<=}z{<=}7.2) permanent magnets which were specifically designed for high temperature applications. The microstructural data were correlated with the magnetic measurements to understand the origin of coercivity. All sintered magnets showed typical cellular and lamellar microstructures. The cell size and coercivity were found to be more sensitive to z than to the Cu content. For a fixed Cu content, by increasing z from 5.8 to 7.2, the cell size was found to vary dramatically from 10 to 80 nm and the coercivity from 5.6 to 40 kOe, respectively. On the other hand, for fixed z, the cell size decreases slightly with increasing Cu content from 0.08 to 0.128 and the corresponding coercivity increases from 23.6 to 40 kOe. Both z and the Cu content show a smaller effect on the cell boundary width and lamella phase density. Domain wall pinning is observed in all magnets studied, irrespective of their cell size. The smaller the cell size, the less wavy the walls are, and the lower the coercivity. The Lorentz microscopy data indicate that the majoritymore » of pinning sites are the cell boundaries with occasional pinning at the intersection of cell boundaries with the lamella phase. (c) 2000 American Institute of Physics.« less

Authors:
 [1];  [1];  [1];  [2];  [2];  [3]
  1. Physics and Astronomy Department, University of Delaware, Newark, Delaware 19716 (United States)
  2. Electron Energy Corporation, Landisville, Pennsylvania 17538 (United States)
  3. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
20216279
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 87; Journal Issue: 9; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SAMARIUM ALLOYS; COBALT ALLOYS; COPPER ALLOYS; IRON ALLOYS; ZIRCONIUM ALLOYS; HARDENING; MICROSTRUCTURE; SINTERING; TRANSMISSION ELECTRON MICROSCOPY; PERMANENT MAGNETS; COERCIVE FORCE; DOMAIN STRUCTURE; EXPERIMENTAL DATA

Citation Formats

Zhang, Yong, Corte-Real, Michelle, Hadjipanayis, George C., Liu, Jinfang, Walmer, Marlin S., and Krishnan, Kannan M. Magnetic hardening studies in sintered Sm(Co,Cu{sub x},Fe,Zr){sub z} 2:17 high temperature magnets. United States: N. p., 2000. Web. doi:10.1063/1.372820.
Zhang, Yong, Corte-Real, Michelle, Hadjipanayis, George C., Liu, Jinfang, Walmer, Marlin S., & Krishnan, Kannan M. Magnetic hardening studies in sintered Sm(Co,Cu{sub x},Fe,Zr){sub z} 2:17 high temperature magnets. United States. doi:10.1063/1.372820.
Zhang, Yong, Corte-Real, Michelle, Hadjipanayis, George C., Liu, Jinfang, Walmer, Marlin S., and Krishnan, Kannan M. Mon . "Magnetic hardening studies in sintered Sm(Co,Cu{sub x},Fe,Zr){sub z} 2:17 high temperature magnets". United States. doi:10.1063/1.372820.
@article{osti_20216279,
title = {Magnetic hardening studies in sintered Sm(Co,Cu{sub x},Fe,Zr){sub z} 2:17 high temperature magnets},
author = {Zhang, Yong and Corte-Real, Michelle and Hadjipanayis, George C. and Liu, Jinfang and Walmer, Marlin S. and Krishnan, Kannan M.},
abstractNote = {Lorentz microscopy combined with conventional transmission electron microscopy were used to image the magnetic domains and microstructures of sintered Sm(Co{sub bal}Cu{sub x}Fe{sub 0.06}Zr{sub 0.03}){sub z} (0.088{<=}x{<=}0.128; 5.8{<=}z{<=}7.2) permanent magnets which were specifically designed for high temperature applications. The microstructural data were correlated with the magnetic measurements to understand the origin of coercivity. All sintered magnets showed typical cellular and lamellar microstructures. The cell size and coercivity were found to be more sensitive to z than to the Cu content. For a fixed Cu content, by increasing z from 5.8 to 7.2, the cell size was found to vary dramatically from 10 to 80 nm and the coercivity from 5.6 to 40 kOe, respectively. On the other hand, for fixed z, the cell size decreases slightly with increasing Cu content from 0.08 to 0.128 and the corresponding coercivity increases from 23.6 to 40 kOe. Both z and the Cu content show a smaller effect on the cell boundary width and lamella phase density. Domain wall pinning is observed in all magnets studied, irrespective of their cell size. The smaller the cell size, the less wavy the walls are, and the lower the coercivity. The Lorentz microscopy data indicate that the majority of pinning sites are the cell boundaries with occasional pinning at the intersection of cell boundaries with the lamella phase. (c) 2000 American Institute of Physics.},
doi = {10.1063/1.372820},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 9,
volume = 87,
place = {United States},
year = {2000},
month = {5}
}