Co-vacancy induced magneto-structural transformation in Co and Ge bidirectional-regulation MnCoGe systems

• Published in: Journal of alloys and compounds 2020-04, Vol.819, p.153061, Article 153061
• Main Authors: Song, Ying, Ma, Shengcan, Yang, Feng, Zhang, Zhishuo, Zhang, Yuxi, Zeng, Hai, Ur Rehman, Sajjad, Feng, Guofang, Luo, Xiaohua, Chen, Changcai, Lu, Zhansheng, Zhong, Zhenchen
• Format: Article
• Language: English
• Subjects: Bidirectional regulation; Coupling; Curie temperature; Magnetic phase diagrams; Magneto-structural coupling; Magnetocaloric effect; Room temperature; Transformations
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.153061

Tuning the structural transformation into the temperature region between the Curie temperatures of Hexagonal and Orthorhombic phases can acquire coincident magneto-structural transformation with a large magnetocaloric effect in MnCoGe alloy. However, the investigations about controlling and achieving magneto-structural coupling in MnCoGe-based alloys usually focus on the unidirectional change among the three elements. Here, we report the first-order magneto-structural coupled transformation in Co and Ge bidirectional-regulation MnCoGe alloys. Resultantly, large magnetocaloric effect is obtained around room temperature in both MnCo1-xGe1+x and MnCo1+yGe1-y systems. The uniform origins of magneto-structural coupling in both systems are explored. [Display omitted] •Co/Ge ratio bidirectional-regulation MnCoGe alloys are prepared.•The coincident magneto-structural transformation is realized simultaneously.•Giant magnetocaloric effect is obtained around room temperature in these two series of alloys.•The introduction of Co-vacancy as the unified origin is proposed to interpret the Tstr-reduction.