The second-order magnetic phase transition and magnetocaloric effect in all-d-metal NiCoMnTi-based Heusler alloys

作者：Fengqi Zhang, K. E. Westra, Qi Shen, Ivan Batashev, Anika Kiecana, Niels van Dijk, E. Brück · 发表于：Journal of Alloys and Compounds · 年份：2022 · DOI：10.1016/j.jallcom.2022.164337 · 被引用次数：64 · 研究领域：Shape Memory Alloy Transformations、Heusler alloys: electronic and magnetic properties、Magnetic and transport properties of perovskites and related materials

The novel all-d-metal Ni(Co)MnTi based magnetic Heusler alloys provide an adjustable giant magnetocaloric effect and good mechanical properties. We report that the second-order magnetic phase transition can be tailored in this all-d-metal NiCoMnTi based Heusler system by optimizing the Mn/Ti ratio, resulting in a reversible ferromagnetic-to-paramagnetic magnetic transition. A candidate material Ni33Co17Mn30Ti20 with a magnetic entropy change ∆Sm of 2.3 Jkg−1K−1 for a magnetic field change of 0–5 T, has been identified. The TC and saturation magnetization MS can be controlled by adjusting the Ni/Co concentration and doping non-magnetic Cu atoms. The compositional maps of TC and MS have been established. Density functional theory (DFT) calculations reveal a direct correlation between the magnetic moments and the Co content. By combining XRD, SQUID, SEM and DFT calculations, the (micro)structural and magnetocaloric properties have been investigated systematically. This study provides a detailed insight in the magnetic phase transition for this all-d-metal Ni(Co)MnTi-based Heusler alloy system.