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Information × Registration Number 0218U005451, 0117U000435 , R & D reports Title Variation of physical properties in ferromagnetic shape memory Heusler alloys under the influence of magnetic field and mechanical stress popup.stage_title Head Kokorin V.,Konopljuk S., Registration Date 28-11-2018 Organization Institute of magnetism NASU and MESU popup.description2 Research in the framework of the current project stage was focused on Heusler Ni-Mn-Sb alloys prospective for magnetic refrigeration. Concurrently, considerable elastoresistive effect discovered in some Heusler Ni-Mn based alloys indicates their possible applications as sensors responding mechanical stress. Simultaneous investigations of mechanical, electrical and structural properties of Ni-Mn-Sb alloys with Fe additions have shown that stress-induced martensitic transformation under uniaxial stress is accompanied by 10-15% growth of electrical resistance typical for the most of shape-memory alloys but far lower than in Ni-Mn-In alloys. Magnetic transition accompanied by blocking (pinning) of ferromagnetic domens or regions due to antiferromagnetic interactions between Sb atoms was found to realize at T ~ 100 K in martensitic phase of Ni-Mn-Sb alloys. Owing to presence of antiferromagnetic interactions below this temperature exchange bias is observed. Magnetization measurements performed in high fields have demonstrated magnetically induced shift of martensitic temperatures dTm/d?0H~ -0.7 K/T. Iron addition is shown to result in growth of magnetization in austenitic phase. Although this can be favorable for value of inverse magnetocaloric effect but iron also leads to increase in amount of ferromagnetic phase in martensite that makes this alloying element unsuitable for enhancing magnetocaloric effect. Nearby Curie temperature, maximum value of adiabatic change of temperature under magnetic field was found, however its magnitude prospective for magnetocaloric applications is reached in high magnetic fields (~5 T). In summary, improvement of functional properties of studied alloys can be achieved by composition tuning aiming at decreasing areas with ferromagnetic ordering in martensitic phase. Product Description popup.authors КозловаЛ.Є. Кокорін В.В. Коноплюк С.М. popup.nrat_date 2020-04-02 Close