Effect of annealing on the magnetic, magnetocaloric and magnetoresistance properties of Ni-Co-Mn-Sb melt spun ribbons

Abstract

The structural, magnetic, magnetocaloric and magnetotransport properties of Ni 46 Co 4 Mn 38 Sb 12 melt spun ribbons have been systematically investigated. The partially ordered B2 phase of the as-spun ribbon transforms to fully ordered L2 1 phase upon annealing, which signifies a considerable change of the atomic ordering in the system. The presence of atomic disorder in the as-spun ribbon gives rise to a higher martensitic transition temperature and a lower magnetization as compared to the bulk sample. However, annealing the ribbons helps in regaining the bulk properties to a large extent. Significant changes in magnetocaloric effect, exchange bias and magnetoresistance have been observed between the as-spun and the annealed ribbons, indicating the role of atomic ordering on the functional as well as fundamental properties in the Heusler system. Importantly, the study shows that one can reduce the hysteresis loss by preparing melt spun alloys and subjecting them to appropriate annealing conditions, which enable them to become practical magnetic refrigerants.

Role of disorder when upscaling magnetocaloric Ni-Co-Mn-Al Heusler alloys from thin films to ribbons

“…As it was previously shown in several studies 15 , 16 , 18 – 20 , annealing can improve the magnetocaloric properties of Heusler alloys. Compared to bulk Heusler alloys, reduced annealing times of around some minutes to hours are typical for melt-spun geometries 6 , owing to their large surface to volume ratio.…”

“…The dependence of the magnetocaloric properties of NiMn-based Heusler alloys on the annealing procedure has been analysed by numerous works 15 , 16 , 18 , 20 . Particularly the response to very short annealing time (<1 h) was studied for a number of magnetocaloric Heusler alloys 16 , 18 , 19 , and explained with the transition from A2 to B2 ordering, like in step 1 of our 3-step scenario above.…”

Magnetocaloric effect in “reduced” dimensions: Thin films, ribbons, and microwires of Heusler alloys and related compounds

“…For the Ni–Mn–Ga system, MCE has been studied in Ni‐rich ribbons . For ribbons from the other Ni–Mn–X systems, MCE has been characterized for ternary Ni–Mn–In , Ni–Mn–Sn , and Ni–Mn–Sb systems, cobalt‐doped Ni–Mn–In and Ni–Mn–Sb , cobalt‐ and iron‐doped Ni–Mn–Sn , and for Ni–Mn–In with partial substitution of In for B, Si, or Ge . Except Ref.…”

Crystallographic features of the martensitic transformation and their impact on variant organization in the intermetallic compound Ni50Mn38Sb12studied by SEM/EBSD

“…As a new member of this family, the Ni-Mn-Sb system has demonstrated multiple functionalities under an actuating magnetic field, such as the shape-memory effect (SME) (Yu et al, 2014), the magnetocaloric effect (MCE) (Nayak et al, 2009;Akkera et al, 2015;Barman & Kaur, 2015), giant magnetoresistance (GMR) (Khan et al, 2013;Sahoo et al, 2013) and exchange bias (EB) (Sharma Akkera et al, 2013;Lee et al, 2013;Barman et al, 2014). These materials have thus been considered as potential candidates for magnetic shapememory, magnetic refrigerant and magnetic recording applications.…”