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Title: Intrinsic magnetic properties of L1(0) FeNi obtained from meteorite NWA 6259

Abstract

FeNi having the tetragonal L1(0) crystal structure is a promising new rare-earth-free permanent magnet material. Laboratory synthesis is challenging, however, tetragonal L1(0) FeNi-the mineral "tetrataenite"-has been characterized using specimens found in nickel-iron meteorites. Most notably, the meteorite NWA 6259 recovered from Northwest Africa is 95 vol.% tetrataenite with a composition of 43 at.% Ni. Hysteresis loops were measured as a function of sample orientation on a specimen cut from NWA 6259 in order to rigorously deduce the intrinsic hard magnetic properties of its L1(0) phase. Electron backscatter diffraction showed that NWA 6259 is strongly textured, containing L1(0) grains oriented along any one of the three equivalent cubic directions of the parent fcc structure. The magnetic structure was modeled as a superposition of the three orthonormal uniaxial variants. By simultaneously fitting first-quadrant magnetization data for 13 different orientations of the sample with respect to the applied field direction, the intrinsic magnetic properties were estimated to be saturation magnetization 4 pi M-s = 14.7 kG and anisotropy field H-a = 14.4 kOe. The anisotropy constant K = 0.84 MJ/m(3) is somewhat smaller than the value K = 1.3 MJ/m(3) obtained by earlier researchers from nominally equiatomic FeNi prepared by neutron irradiation accompaniedmore » by annealing in a magnetic field, suggesting that higher Ni content (fewer Fe antisite defects) may improve the anisotropy. The fit also indicated that NWA 6259 contains one dominant variant (62% by volume), the remainder of the sample being a second variant, and the third variant being absent altogether. (C) 2015 AIP Publishing LLC.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1211348
DOE Contract Number:  
0472-1537
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English

Citation Formats

Poirier, E, Pinkerton, FE, Kubic, R, Mishra, RK, Bordeaux, N, Mubarok, A, Lewis, LH, Goldstein, JI, Skomski, R, and Barmak, K. Intrinsic magnetic properties of L1(0) FeNi obtained from meteorite NWA 6259. United States: N. p., 2015. Web. doi:10.1063/1.4916190.
Poirier, E, Pinkerton, FE, Kubic, R, Mishra, RK, Bordeaux, N, Mubarok, A, Lewis, LH, Goldstein, JI, Skomski, R, & Barmak, K. Intrinsic magnetic properties of L1(0) FeNi obtained from meteorite NWA 6259. United States. doi:10.1063/1.4916190.
Poirier, E, Pinkerton, FE, Kubic, R, Mishra, RK, Bordeaux, N, Mubarok, A, Lewis, LH, Goldstein, JI, Skomski, R, and Barmak, K. Thu . "Intrinsic magnetic properties of L1(0) FeNi obtained from meteorite NWA 6259". United States. doi:10.1063/1.4916190.
@article{osti_1211348,
title = {Intrinsic magnetic properties of L1(0) FeNi obtained from meteorite NWA 6259},
author = {Poirier, E and Pinkerton, FE and Kubic, R and Mishra, RK and Bordeaux, N and Mubarok, A and Lewis, LH and Goldstein, JI and Skomski, R and Barmak, K},
abstractNote = {FeNi having the tetragonal L1(0) crystal structure is a promising new rare-earth-free permanent magnet material. Laboratory synthesis is challenging, however, tetragonal L1(0) FeNi-the mineral "tetrataenite"-has been characterized using specimens found in nickel-iron meteorites. Most notably, the meteorite NWA 6259 recovered from Northwest Africa is 95 vol.% tetrataenite with a composition of 43 at.% Ni. Hysteresis loops were measured as a function of sample orientation on a specimen cut from NWA 6259 in order to rigorously deduce the intrinsic hard magnetic properties of its L1(0) phase. Electron backscatter diffraction showed that NWA 6259 is strongly textured, containing L1(0) grains oriented along any one of the three equivalent cubic directions of the parent fcc structure. The magnetic structure was modeled as a superposition of the three orthonormal uniaxial variants. By simultaneously fitting first-quadrant magnetization data for 13 different orientations of the sample with respect to the applied field direction, the intrinsic magnetic properties were estimated to be saturation magnetization 4 pi M-s = 14.7 kG and anisotropy field H-a = 14.4 kOe. The anisotropy constant K = 0.84 MJ/m(3) is somewhat smaller than the value K = 1.3 MJ/m(3) obtained by earlier researchers from nominally equiatomic FeNi prepared by neutron irradiation accompanied by annealing in a magnetic field, suggesting that higher Ni content (fewer Fe antisite defects) may improve the anisotropy. The fit also indicated that NWA 6259 contains one dominant variant (62% by volume), the remainder of the sample being a second variant, and the third variant being absent altogether. (C) 2015 AIP Publishing LLC.},
doi = {10.1063/1.4916190},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}