Effect of Ge substitution on magnetic properties in the itinerant chiral magnet MnSi

Journal Article · 14 October 2019 · Physical Review Materials

DOI: https://doi.org/10.1103/PhysRevMaterials.3.104408 · OSTI ID:1570897

Aji, Seno  ^[1]; Ishida, Hidesato ^[1]; Okuyama, Daisuke ^[1]; Nawa, Kazuhiro  ^[1]; Hong, Tao  ^[2]; Sato, Taku J. ^[1]

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1. Tohoku Univ., Sendai (Japan)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

We have investigated the effect of Ge substitution on the magnetic ordering in the B20 itinerant chiral magnet MnSi prepared by melting and annealing under ambient pressure. From a metallurgical survey, the solubility limit of Ge was found to be x = 0.144(5) with annealing temperature T_an = 1073 K. Magnetization measurements on MnSi_1–xGe_x samples show that the helical ordering temperature T_c increases rapidly in the low-x range, whereas it becomes saturated at higher concentration x > 0.1. Here, the Ge substitution also increases both the saturation magnetization M_s and the critical field to the fully polarized state H_c2. In contrast to the saturation behavior of T_c, those parameters increase linearly up to the highest Ge concentration investigated. In the temperature-magnetic field phase diagram, we found enlargement of the skyrmion phase region for large x samples. We, furthermore, observed the nonlinear behavior of helical modulation vector k as a function of Ge concentration, which can be described qualitatively using the mean field approximation.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1570897
• Journal Information: Physical Review Materials, Journal Name: Physical Review Materials Journal Issue: 10 Vol. 3; ISSN PRMHAR; ISSN 2475-9953
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English