Structural and Magnetic Properties of MnCo1−xFexGe1−ySiy (x, y = 0, 0.5)

• Published in: MATERIALS TRANSACTIONS Vol. 66; no. 6; pp. 758 - 763
• Main Authors: Mitsui, Yoshifuru, Sueyoshi, Yukinari, Koyama, Keiichi, Kobayashi, Ryota, Onoue, Masahira, Umetsu, Rie Y.
• Format: Journal Article
• Language: English
• Published: Sendai The Japan Institute of Metals and Materials 01.06.2025; 公益社団法人 日本金属学会; Japan Science and Technology Agency
• Subjects: antiferromagnetic; Antiferromagnetism; Crystal structure; ferromagnetic; Ferromagnetism; Hysteresis; Magnetic fields; Magnetic properties; Magnetization curves; metamagnetic transition; MnCoGe; MnCoSi; Room temperature; X ray powder diffraction
• ISSN: 1345-9678; 1347-5320
• DOI: 10.2320/matertrans.MT-MBW2024001

Magnetic and structural properties of MnCo1−xFexGe1−ySiy (x, y = 0, 0.5) were investigated using X-ray powder diffraction and magnetization measurements in the temperature (T) range from 5 to 370 K and in magnetic fields up to μ0H = 5 T. At room temperature, MnCoGe and MnCoGe0.5Si0.5 were the orthorhombic crystal structure (M-phase), MnCo0.5Fe0.5Ge was the hexagonal crystal structure (P-phase), and MnCo0.5Fe0.5Ge0.5Si0.5 had two-phase coexistence of the M- and P-phases. MnCoGe and MnCo0.5Fe0.5Ge were a simple ferromagnetic and their Curie temperatures (TC) were determined to be 340 K and 200 K, respectively. MnCoGe0.5Si0.5 and MnCo0.5Fe0.5Ge0.5Si0.5 in μ0H ≤ 1 T showed a gentle dip in thermomagnetic curves at 10 ≤ T ≤ 100 K below TC which disappears when a magnetic field of μ0H > 3 T was applied. The magnetization curves of MnCoGe0.5Si0.5 and MnCo0.5Fe0.5Ge0.5Si0.5 at 5 K exhibited that a metamagnetic transition with the magnetic hysteresis in 0 < μ0H < 3 T. Our results suggest that substituting Fe for Co in MnCoGe system weakens the ferromagnetic interaction, whereas substituting Si for Ge strengthens the antiferromagnetic interaction.