In this study, the effect, Cd doping on structural, magnetic and magnetocaloricproperties of Ni-Mn-Sn ferromagnetic shape memory alloys have been studied. In this thesis, Ni47Mn40Sn13-xCdx (x= 0, 0.75, 1, 1.25) ferromagnetic shape memoryalloys were prepared by mechanical alloying. For preparing the samples, the powders of primary material were ball-milledunder an argon atmosphere 30 hours and then, bulk samples werecompacted and encapsulated in quartz tubes under high vacuum and annealedfor 16 hours at 950 Cfollowed by rapid quenching in ice-water mixture. The X-ray diffraction patternof the samples indicate that the x=0, 0.75, 1 show single phase and have L21 structure but in Cd1.25Sn go out of single phase. The martensitictransformation (MT) temperature enhanced for all doped samples to roomtemperature. Change of the temperature is related to the valence electron perunit (e/a) and lattice parameter. Magnetic susceptibility of all the samplesindicates a magnetic transition. Magnetocaloric effect was measured bothdirestly and indirectly. Magnetocaloric effect enhances by doping Cd instead ofSn. As a result magnetic entropy change increasises from 7.6 J.kg -1 .K -1 for undoped sample to tha values of 11.2, 13.1 and 12.0 for samples withx=0.75, 1 and 1.25 respectively. Direct magnetocaloric measurement shows thatthe change of adiabatic temperature increase from 0.9 K for undoped sample to1.5 K for the sample of x=0.75. Both direct and indirect measurements provesthat the Cd doping enhances the the value of magnetocaloric effect. In this study,the effect, Cd doping on structural, magnetic and magnetocaloric properties ofNi-Mn-Sn ferromagnetic shape memory alloys have been studied. Inthis thesis, Ni47Mn40Sn13-xCdx(x= 0, 0.75, 1, 1.25) ferromagnetic shape memory alloys wereprepared by mechanical alloying. For preparing the samples, the powders of primary material were ball-milled under anargon atmosphere 30 hours and then, bulk samples were compacted and encapsulated in quartz tubesunder high vacuum and annealed for16 hours at 950 C followed by rapid quenching inice-water mixture. The X-ray diffraction pattern of the samples indicate thatthe x=0, 0.75, 1 show single phase and have L21structure but in Cd1.25Sn go out of single phase. Themartensitic transformation (MT) temperature enhanced for all doped samples toroom temperature. Change of the temperature is related to the valence electronper unit (e/a) and lattice parameter. Magnetic susceptibility of all thesamples indicates a magnetic transition. Magnetocaloric effect was measuredboth direstly and indirectly. Magnetocaloric effect enhances by doping Cdinstead of Sn. As a result magnetic entropy change increasises from 7.6 J.kg -1 .K -1 for undoped sample to tha values of 11.2, 13.1 and 12.0 for samples withx=0.75, 1 and 1.25 respectively. Direct magnetocaloric measurement shows thatthe change of adiabatic temperature increase from 0.9 K for undoped sample to1.5 K for the sample of x=0.75. Both direct and indirect measurements provesthat the Cd doping enhances the the value of magnetocaloric effect. Keywords: Magnetocaloric effect, Ferromagnetic shape memory alloys, martensitic transformation,exchange bias effect
