Determination of hyperfine fields and atomic ordering in NiMnFeGe exhibiting martensitic transformation

• Published in: Nukleonika Vol. 60; no. 1; pp. 127 - 131
• Main Authors: Satuła, Dariusz, Szymański, Krzysztof, Rećko, Katarzyna, Olszewski, Wojciech, Kalska-Szostko, Beata
• Format: Journal Article
• Language: English
• Published: De Gruyter Open 01.03.2015; Sciendo
• Subjects: atomic ordering; martensitic transition; Mössbauer spectroscopy; X-ray diffraction
• ISSN: 0029-5922; 0029-5922
• DOI: 10.1515/nuka-2015-0026

The hyperfine fields and atomic ordering in Ni Fe MnGe ( = 0.1, 0.2, 0.3) alloys were investigated using X-ray diffraction and Mössbauer spectroscopy at room temperature. The X-ray diffraction measurements show that the samples with = 0.2, 0.3 crystallized in the hexagonal Ni In-type of structure, whereas in the sample with = 0.1, the coexistence of two phases, Ni In- and orthorhombic TiNiSi-type of structures, were found. The Mössbauer spectra measured with = 0.2, 0.3 show three doublets with different values of isomer shift (IS) and quadrupole splitting (QS) related to three different local surroundings of Fe atoms in the hexagonal Ni In-type structure. It was shown that Fe atoms in the hexagonal Ni In-type structure of as-cast Ni Fe MnGe alloys are preferentially located in Ni sites and small amount of Fe is located in Mn and probably in Ge sites. The spectrum for = 0.1 shows the doublets in the central part of spectrum and a broad sextet. The doublets originate from the Fe atoms in the paramagnetic state of hexagonal Ni In-type structure, whereas the sextet results from the Fe atoms in orthorhombic TiNiSi-type structure.