Tuning martensitic transitions in (MnNiSi)0.65(Fe2Ge)0.35 through heat treatment and hydrostatic pressure
- Louisiana State Univ., Baton Rouge, LA (United States)
- Southern Illinois Univ., Carbondale, IL (United States)
A first-order magneto-structural transition from a ferromagnetic orthorhombic TiNiSi-type martensite phase to a paramagnetic hexagonal Ni2In-type austenite phase was observed in (MnNiSi)0.65(Fe2Ge)0.35. In this work, we demonstrate that the first-order magneto-structural transition temperature for a given composition is tunable over a wide temperature range through heat treatment and hydrostatic pressure. The first-order transition temperature was reduced by over 100 K as the annealing temperature went from 600 to 900 °C, and this first-order transition was converted to second order when the sample was annealed at 1000 °C. The maximum magnetic-induced isothermal entropy change with μ0ΔH=7 T reaches -58 J/kg K for the sample annealed at 600 °C, and the relative cooling power reaches 558 J/kg for the sample annealed at 700 °C. Similar to the influence of annealing temperatures, the first-order martensitic transition temperatures were reduced as the application of hydrostatic pressure increased until they were converted to second order. Our results suggest that the (MnNiSi)0.65(Fe2Ge)0.35 system is a promising platform for tuning magneto-structural transitions and the associated magnetocaloric effects. Furthermore, a similar heat treatment methodology or application of hydrostatic pressure can be applied to MnNiSi-based shape memory alloys to tailor their working transition temperatures.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Louisiana State Univ., Baton Rouge, LA (United States); Southern Illinois Univ., Carbondale, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-06CH11357; FG02-13ER46946; FG02-06ER46291; SC0012432; NSF-DMR- 1306392; SC0010521
- OSTI ID:
- 1484787
- Alternate ID(s):
- OSTI ID: 1872463
- Journal Information:
- Journal of Applied Physics, Vol. 124, Issue 20; ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
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