Microstructure and spin polarization of quaternary Co2Cr1-xVxAl, Co2V1-xFexAl and Co2Cr1-xFexAl Heusler alloys

S. V. Karthik; A. Rajanikanth; Y. K. Takahashi; T. Ohkubo; K. Hono

doi:10.1016/j.actamat.2007.03.003

Microstructure and spin polarization of quaternary Co₂Cr_1-xV_xAl, Co₂V_1-xFe_xAl and Co₂Cr_1-xFe_xAl Heusler alloys

S. V. Karthik, A. Rajanikanth, Y. K. Takahashi, T. Ohkubo, K. Hono^*

^*Corresponding author for this work

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

52 Citations (Scopus)

Abstract

The microstructures, magnetic properties and spin polarization of quaternary Co₂Cr_1-xV_xAl, Co₂V_1-xFe_xAl and Co₂Cr_1-xFe_xAl alloys were investigated. Phase separation into A2 and B2/L2₁ structure occurs in Co₂CrAl and Co₂Cr_0.6Fe_0.4Al, whereas Co₂FeAl exhibits a single-phase B2 structure. The ordered L2₁ structure becomes more stable with increasing vanadium concentration (x ≥ 0.35). The saturation magnetization measured at 5 K for Co₂Cr_1-xV_xAl alloy changes from 1.4 to 2.0 μ_B when x increases from 0.0 to 0.5 and then becomes 1.4 μ_B for x = 1.0. This behavior can be attributed to the variation in the local magnetic moment of Co atoms. The saturation magnetization of Co₂V_1-xFe_xAl and Co₂Cr_1-xFe_xAl alloys increases with increasing Fe concentration. The spin polarization decreases from 0.62 to 0.56 with increasing x for Co₂Cr_1-xFe_xAl alloy. Also, the spin polarization decreases with increasing x for Co₂Fe_1-xV_xAl and Co₂Cr_1-xV_xAl alloys. Possible reasons for the reduced spin polarization in these alloys are discussed.

Original language	English
Pages (from-to)	3867-3874
Number of pages	8
Journal	Acta Materialia
Volume	55
Issue number	11
DOIs	https://doi.org/10.1016/j.actamat.2007.03.003
Publication status	Published - 2007 Jun
Externally published	Yes

Keywords

Half-metals
Heusler alloys
Microstructure
Spin polarization

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

Access to Document

10.1016/j.actamat.2007.03.003

Cite this

@article{d9097b64a52b4735b1dd0d371f96beaa,

title = "Microstructure and spin polarization of quaternary Co2Cr1-xVxAl, Co2V1-xFexAl and Co2Cr1-xFexAl Heusler alloys",

abstract = "The microstructures, magnetic properties and spin polarization of quaternary Co2Cr1-xVxAl, Co2V1-xFexAl and Co2Cr1-xFexAl alloys were investigated. Phase separation into A2 and B2/L21 structure occurs in Co2CrAl and Co2Cr0.6Fe0.4Al, whereas Co2FeAl exhibits a single-phase B2 structure. The ordered L21 structure becomes more stable with increasing vanadium concentration (x ≥ 0.35). The saturation magnetization measured at 5 K for Co2Cr1-xVxAl alloy changes from 1.4 to 2.0 μB when x increases from 0.0 to 0.5 and then becomes 1.4 μB for x = 1.0. This behavior can be attributed to the variation in the local magnetic moment of Co atoms. The saturation magnetization of Co2V1-xFexAl and Co2Cr1-xFexAl alloys increases with increasing Fe concentration. The spin polarization decreases from 0.62 to 0.56 with increasing x for Co2Cr1-xFexAl alloy. Also, the spin polarization decreases with increasing x for Co2Fe1-xVxAl and Co2Cr1-xVxAl alloys. Possible reasons for the reduced spin polarization in these alloys are discussed.",

keywords = "Half-metals, Heusler alloys, Microstructure, Spin polarization",

author = "Karthik, {S. V.} and A. Rajanikanth and Takahashi, {Y. K.} and T. Ohkubo and K. Hono",

note = "Funding Information: This work was supported in part by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (B), 17360346, 2005. We thank Professor H. Asano at Nagoya University and Professor S. Mitani at the Institute for Materials Research, Tohoku University, for valuable advice in the point contact Andreev reflection measurement, and Professor K. Inomata for discussion.",

year = "2007",

month = jun,

doi = "10.1016/j.actamat.2007.03.003",

language = "English",

volume = "55",

pages = "3867--3874",

journal = "Acta Materialia",

issn = "1359-6454",

publisher = "Elsevier Limited",

number = "11",

}

TY - JOUR

T1 - Microstructure and spin polarization of quaternary Co2Cr1-xVxAl, Co2V1-xFexAl and Co2Cr1-xFexAl Heusler alloys

AU - Karthik, S. V.

AU - Rajanikanth, A.

AU - Takahashi, Y. K.

AU - Ohkubo, T.

AU - Hono, K.

N1 - Funding Information: This work was supported in part by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (B), 17360346, 2005. We thank Professor H. Asano at Nagoya University and Professor S. Mitani at the Institute for Materials Research, Tohoku University, for valuable advice in the point contact Andreev reflection measurement, and Professor K. Inomata for discussion.

PY - 2007/6

Y1 - 2007/6

N2 - The microstructures, magnetic properties and spin polarization of quaternary Co2Cr1-xVxAl, Co2V1-xFexAl and Co2Cr1-xFexAl alloys were investigated. Phase separation into A2 and B2/L21 structure occurs in Co2CrAl and Co2Cr0.6Fe0.4Al, whereas Co2FeAl exhibits a single-phase B2 structure. The ordered L21 structure becomes more stable with increasing vanadium concentration (x ≥ 0.35). The saturation magnetization measured at 5 K for Co2Cr1-xVxAl alloy changes from 1.4 to 2.0 μB when x increases from 0.0 to 0.5 and then becomes 1.4 μB for x = 1.0. This behavior can be attributed to the variation in the local magnetic moment of Co atoms. The saturation magnetization of Co2V1-xFexAl and Co2Cr1-xFexAl alloys increases with increasing Fe concentration. The spin polarization decreases from 0.62 to 0.56 with increasing x for Co2Cr1-xFexAl alloy. Also, the spin polarization decreases with increasing x for Co2Fe1-xVxAl and Co2Cr1-xVxAl alloys. Possible reasons for the reduced spin polarization in these alloys are discussed.

AB - The microstructures, magnetic properties and spin polarization of quaternary Co2Cr1-xVxAl, Co2V1-xFexAl and Co2Cr1-xFexAl alloys were investigated. Phase separation into A2 and B2/L21 structure occurs in Co2CrAl and Co2Cr0.6Fe0.4Al, whereas Co2FeAl exhibits a single-phase B2 structure. The ordered L21 structure becomes more stable with increasing vanadium concentration (x ≥ 0.35). The saturation magnetization measured at 5 K for Co2Cr1-xVxAl alloy changes from 1.4 to 2.0 μB when x increases from 0.0 to 0.5 and then becomes 1.4 μB for x = 1.0. This behavior can be attributed to the variation in the local magnetic moment of Co atoms. The saturation magnetization of Co2V1-xFexAl and Co2Cr1-xFexAl alloys increases with increasing Fe concentration. The spin polarization decreases from 0.62 to 0.56 with increasing x for Co2Cr1-xFexAl alloy. Also, the spin polarization decreases with increasing x for Co2Fe1-xVxAl and Co2Cr1-xVxAl alloys. Possible reasons for the reduced spin polarization in these alloys are discussed.

KW - Half-metals

KW - Heusler alloys

KW - Microstructure

KW - Spin polarization

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JF - Acta Materialia

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