Abstract
The influence of excess Mn on the magnetoelastic ferromagnetic-to-antiferromagnetic transition Tt in the magnetocaloric compound (Mn,Cr)2Sb has been studied. With increasing excess Mn the magnetoelastic transition temperature for (Mn,Cr)2Sb initially increases and then decreases. This trend is accompanied by a strong reduction of the (Mn,Cr)Sb secondary phase. With increasing excess Mn a higher Cr content was found in the (Mn,Cr)Sb secondary phase in comparison to the matrix phase. This competition for Cr leads to a nonlinear dependence of Tt with increasing excess Mn at a fixed nominal Cr content. However, we observed that Tt depends linear on the c/a ratio for a wide range of temperatures from 170 to 350 K. A compositional diagram of the c/a ratio was constructed to assist the selection of (Mn,Cr)2Sb alloys with a desired transition temperature.
Highlights
The magnetocaloric effect (MCE), associated with either an iso thermal entropy change or an adiabatic temperature change in the presence of a change in magnetic field, can be used for magnetic refrigeration and waste heat recovery [1,2]
The microstructure was analysed by Electron Probe Micro Analysis (EPMA) model JEOL JXA 8900R equipped with the Wavelength Dis persive Spectrometry (WDS) and the Scanning Electron Microscopy (SEM) model FEI Quanta FEG 450 equipped with the Energy Dispersive Xray Spectroscopy (EDS)
The fraction of the (Mn,Cr)Sb secondary phase strongly reduces with increasing excess Mn, while the magnetoelastic transition temperature initially in creases and decreases with excess Mn
Summary
The magnetocaloric effect (MCE), associated with either an iso thermal entropy change or an adiabatic temperature change in the presence of a change in magnetic field, can be used for magnetic refrigeration and waste heat recovery [1,2]. The FOMT has been studied in many Mn2Sb-based compounds with elemental substitution such as V [8], Cr [5], Zn [9], Co [10] on the Mn sites or Sn [11], As [12], Ge[13], Bi [14,15] on the Sb site Among these compounds, Cr-doped Mn2Sb is one of the most pro mising magnetocaloric candidate materials with a wide range of FOMT temperatures ranging from 220 to 340 K, a narrow thermal hysteresis (less than 2 K), a large inverse magnetocaloric entropy change of 7.5 J/kg K [5] and an adiabatic temperature change of 2 K under a field change of 5 T [7]. The Mn atoms occupy two different crystallographic sites: Mn-I (2a) with a magnetic
Sign-in/Register to view highlights & summary 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.
