abstract
The competition between the stability of the cubic and hexagonal full Heusler alloys and the implications concerning their magnetic properties were systematically studied through the detailed structural and magnetic characterization of the Fe2Mn(Si1-xGex) system. This system was specifically chosen as the parent compositions are cubic (x = 0) and hexagonal (x = 1). It is found that the formation of hexagonal phases occurs for the x >= 0.6 samples, whereas its phase fraction monotonically increases with x until the pure hexagonal Fe2MnGe is formed. The change in structure results in high sensitiveness of both the saturation of magnetization (MS) and Curie temperature (TC) with x values, related to a strong magnetocrystalline anisotropy of the hexagonal phase. Both cubic and hexagonal magnetic features were qualitatively reproduced by Density Functional Theory (DFT) calculations. This work provides an experimental and theoretical foundation for further design of Heusler systems with controlled structures and magnetic properties. (c) 2021 Elsevier B.V. All rights reserved.
keywords
MAGNETIC-PROPERTIES; PHASE-STABILITY; APPROXIMATION; CRYSTAL
subject category
Chemistry; Materials Science; Metallurgy & Metallurgical Engineering
authors
Pimentel, B; Andrade, VM; de Paula, VG; Pirota, KR; Beron, F; Cardoso, MA; Goncalves, JN; Amaral, JS; dos Santos, AM; Reis, MS
our authors
João Cunha de Sequeira Amaral
Assistant Researcher
João Nuno Santos Gonçalves
Junior Researcher
Marita Alves Cardoso
PhD StudentProjects
Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Projeto de Investigação Exploratória: João Amaral (IF/01089/2015)
acknowledgements
MSR thanks the Brazilian agencies CNPq, FAPERJ, and PROPPI-UFF for financial support. BMP thanks the CNPq for financial support. VGP thanks the CNPq for the financial support under grant no. 160744/2019-9. VMA thanks IFIMUP and FCT for the contract under the project POCI-01-0145-FEDER-028676 and the financial support through the UIDB/04968/2020. MSR belongs to the INCT of Refrigeracao e Termofisica, funding by CNPq by grant number 465448/2014-3. This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) - Finance Code 001 and project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. This work was also financed by the Fundacao de Amparo a Pesquisa do Estado de SAo Paulo, Brasil (FAPESP) - Project No. 2017/10581-1. JSA acknowledges FCT for grant IF/01089/2015. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.