TY - JOUR
T1 - Acceleration of B2/L21 order-disorder transformation in Ni2MnAl Heusler alloys by in-magnetic-field annealing
AU - Kobayashi, Ryota
AU - Mitsui, Yoshifuru
AU - Umetsu, Rie Y.
AU - Takahashi, Kohki
AU - Koyama, Keiichi
N1 - Funding Information:
This work was partly supported by KAKENHI 20K15016. R. K. is grateful to the JSPS Research Fellowships for Young Scientists ( 19J12731 ). In-field heat treatment and magnetization measurements were carried out at the High Field Laboratory for Superconducting Materials (Project No. 19H0082), and Cooperative Research and Development Center for Advanced Materials, Institute for Materials Research, Tohoku University, respectively.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - Ferromagnetic L21 phase of Ni2MnAl with high order degree is difficult to synthesize because of low L21/B2 order-disorder transformation temperature. It is found that magnetic field accelerated the transformation from the antiferromagnetic disordered B2 to ordered L21 phase. Magnetization increased by in-magnetic-field annealing at 673 K, which indicated the acceleration of the ordering to L21 phase. Magnetic field effects on the B2/L21 order-disorder transformation were discussed based on magnetic-field-induced change of transformation temperature, enhancement of degree of order at annealing temperature, and reduction of critical radius of L21 nuclei. Growth kinetics of L21 phase were evaluated by Johnson-Mehl-Avrami equation, which indicated that 15-T annealing accelerated the growth of L21 phase 5.7 times faster than zero-field annealing. Our results showed that magnetic field can contribute to shortening the annealing time for synthesis of ferromagnetic L21-Ni2MnAl alloy.
AB - Ferromagnetic L21 phase of Ni2MnAl with high order degree is difficult to synthesize because of low L21/B2 order-disorder transformation temperature. It is found that magnetic field accelerated the transformation from the antiferromagnetic disordered B2 to ordered L21 phase. Magnetization increased by in-magnetic-field annealing at 673 K, which indicated the acceleration of the ordering to L21 phase. Magnetic field effects on the B2/L21 order-disorder transformation were discussed based on magnetic-field-induced change of transformation temperature, enhancement of degree of order at annealing temperature, and reduction of critical radius of L21 nuclei. Growth kinetics of L21 phase were evaluated by Johnson-Mehl-Avrami equation, which indicated that 15-T annealing accelerated the growth of L21 phase 5.7 times faster than zero-field annealing. Our results showed that magnetic field can contribute to shortening the annealing time for synthesis of ferromagnetic L21-Ni2MnAl alloy.
KW - Ferromagnetic materials
KW - Heusler phases
KW - High magnetic fields
KW - Order-disorder phenomena
KW - Phase transformation kinetics
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U2 - 10.1016/j.jmmm.2021.168908
DO - 10.1016/j.jmmm.2021.168908
M3 - Article
AN - SCOPUS:85120958255
VL - 547
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
SN - 0304-8853
M1 - 168908
ER -