Magnetic order of intermetallic FeGa3-yGey studied by mu SR and Fe-57 Mossbauer spectroscopy

Author(s)

Munevar, J. ; Cabrera-Baez, M. ; Alzamora, M. ; Larrea, J. ; Bittar, E. M. ; Baggio-Saitovitch, E. ; Litterst, F. J. ; Ribeiro, R. A. ; Avila, M. A. ; Morenzoni, E.

• Document type: Journal article
• Source: PHYSICAL REVIEW B; v. 95, n. 12, p. 8-pg., 2017-03-31.

Abstract

Temperature-dependent magnetization, muon spin rotation, and Fe-57 Mossbauer spectroscopy experiments performed on crystals of intermetallic FeGa3-yGey (y = 0.11,0.14,0.17,0.22,0.27,0.29,0.32) are reported. Whereas at y = 0.11 even a sensitive magnetic microprobe such as mu SR does not detect magnetism, all other samples display weak ferromagnetism with a magnetic moment of up to 0.22 mu(B) per Fe atom. As a function of doping and of temperature, a crossover from short-range to long-range magnetic order is observed, characterized by a broadly distributed spontaneous internal field. However, y = 0.14 and 0.17 remain in the short-range-ordered state down to the lowest investigated temperature. The transition from short-range to long-range order appears to be accompanied by a change of the character of the spin fluctuations, which exhibit a spin-wave excitation signature in the long-range-order part of the phase diagram. Mossbauer spectroscopy for y = 0.27 and 0.32 indicates that the internal field lies in the plane perpendicular to the crystallographic c axis. The field distribution and its evolution with doping suggest that the details of the Fe magnetic moment formation and the consequent magnetic state are determined not only by the dopant concentration, but also by the way the replacement of the Ga atoms surrounding the Fe is accomplished. (AU)

• FAPESP's process: 11/19924-2 - Study and development of advanced novel materials: electronic, magnetic and nanostructured: an interdisciplinary approach
• Grantee: Carlos Rettori
• Support Opportunities: Research Projects - Thematic Grants