Abstract
Medical applications of magnetocaloric effect (MCE) require possibility for precision shift of a temperature of the magnetic phase transition at the same MCE value and minimize irreversibility. Thus, detail dynamic MCE investigation of such alloys with non-toxic biocompatible dopants need to be done. In present work, the giant magnetocaloric effect, which is observed in the whole family of Fe-Rh alloys, has been investigated in Pd-doped samples in slowly cycled magnetic fields of up to 1.8 T in magnitude for a range of temperatures, 250 K < T < 350 K. The shift of the ferromagnetic/antiferromagnetic transition temperature down towards room temperature and the decrease in the MCE have been observed in these alloys in comparison with a quasi-equiatomic FeRh alloy. The measurements have also shown an asymmetric behaviour of the first order magnetic phase transition with respect to whether the transition is traversed by heating from lower temperatures or cooling from above. These peculiarities have been explained in the framework of the ab-initio density functional theory-based disordered local moment theory of the MCE. The results have been compared with the those for the non-doped FeRh alloy. Thus features of the first order magnetic phase transition that these alloys have in common have been revealed which enable some predictions to be made appropriate for practical applications.
Highlights
Conventional nearly equiatomic stoichiometric FeRh alloys exhibit a giant magnetocaloric effect (MCE) but have some limitations for widespread use in magnetic refrigeration technology
That ΔT(H) measurements were performed at magnetic field change rates of 1 T/s – 5 T/s but since they were practically identical here we present the ones obtained at 1 T/s
Each material showed a non-symmetric character of its magnetocaloric properties on heating and cooling which was demonstrated by the presence/absence of the ‘irreversibility’ of the sample’s temperature to its initial value during a full cycle of the magnetic field on heating/cooling
Summary
Conventional nearly equiatomic stoichiometric FeRh alloys exhibit a giant magnetocaloric effect (MCE) but have some limitations for widespread use in magnetic refrigeration technology. Among these are the sharp ferromagnetic/antiferromagnetic transition, the relatively high transition temperature and, the high cost of Rh as a constituent of the working body of a refrigerator [1,2,3,4]. The obvious idea is to dope the pure alloy having CsCl-type structure with some elements so that the crucial parameters are adjusted to more suitable values. The idea of this work is to move phase transition temperature around of human body temperature region at saving MCE value. For practical applications the shift of the MCE maximum during magnetization and demagnetization processes should be considered [12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
