Research articlesDirect and indirect measurements of the magnetic and magnetocaloric properties of Ni0.895Cr0.105MnGe1.05 melt-spun ribbons in high magnetic fields
Introduction
The magnetocaloric effect (MCE) is a magneto-thermal property of any ferromagnetic (FM) material that is characterized by the thermal dependency of both the isothermal magnetic entropy change (ΔSM) and the adiabatic temperature change (ΔTad) in response to the change in an external magnetic field µoH. Both physical quantities show their maximum absolute values, |ΔSMpeak| and ΔTadmax, near the Curie temperature (TC). However, several material families such as Gd-Si-Ge, La-Fe-Si, Mn-Fe-P, Mn-As-Sb, and Ni-Mn-(In,Ga,Sn) Heusler alloys undergo giant first-order magnetostructural transitions (MSTs) associated with coupled magnetic and structural transitions, resulting in large MCEs [1], [2], [3], [4], [5], [6]. The large MCEs displayed by these materials have attracted attention in the last two decades due to their potential application in magnetic refrigeration, an emerging solid-state cooling technology that is environmentally friendly and energy efficient compared to traditional refrigeration [7], [8].
Recently, alloys derived from the stoichiometric 1:1:1 MnNiGe and MnCoGe compounds, belonging to the MnTX (T = 3d transition elements and X = Ge, Si) material family have been actively studied since they exhibit large MCEs associated with a change in crystal structure from a high temperature austenite to a low temperature martensite structure. The crystal structure of the high temperature austenite phase is hexagonal (Ni2In-type, space group P63/mmc) and the low temperature martensite phase is orthorhombic (TiNiSi-type, space group Pnma). In stoichiometric NiMnGe and MnCoGe alloys, the martensitic transitions take place at temperatures Tt = 470 K and 650 K, far above the magnetic transitions at the Neel (TN = 346 K) and Curie (TC ∼334 K) temperatures, respectively [9], [10]. A coincidence of the magnetic and structural transitions, i.e., the magnetostructural transitions, resulting in giant and tunable MCEs in terms of |ΔSMpeak|, have already been reported in these systems by changes in stoichiometry, adding interstitial atoms, doping, application of external pressure, and isostructural alloying [see, for instance, [11], [12], [13], [14], [15], [16], [17], [18], [19] and Refs. therein].
It is well known that the MCE can be characterized by two important parameters, ΔSM and ΔTad. Both quantities are equally important to evaluate the performance of a magnetocaloric material for refrigeration purposes. For applications, not only large ΔSMpeak values but also a large ΔTadmax is desired since it acts as a driving force for heat transfer from the cold to the hot reservoirs during a refrigeration cycle. Reports [[11], [12], [13], [14], [15], [16], [17], [18], [19] and Refs. therein] show that the MCE in NiMnGe and MnCoGe based alloys have extensively been studied through indirect measurements, i.e., by experimentally determining ΔSM(T) from a set of isothermal magnetization M(µoH) curves measured through the phase transition. Large |ΔSMpeak| values up to 37.8 J kg−1 K−1 (for µoΔH = 2 T at 192 K), 53.3 J kg−1 K−1 (for µoΔH = 5 T at 321 K), and 47.3 J kg−1 K−1 (for µoΔH = 5 T at 287 K) have been reported for (Mn,Fe)NiGe, (Mn,Cu)CoGe, and MnCoGeB0.02 alloys, respectively [20], [21], [22]. However, reports on the direct measurements, i.e., ΔTad(T), a more reliable and straightforward measurement, in these systems are scarce [22], [23], [24].
In this work we present the experimental results on the MCE properties of Ni0.895Cr0.105MnGe1.05 ribbons using both indirect and direct methods with a focus on the latter. The current study provides an opportunity to understand the magnetic and MCE properties of this system at high magnetic fields up to 10 T.
Section snippets
Experiment
Melt-spun ribbon flakes of nominal composition Ni0.895Cr0.105MnGe1.05 were fabricated from a bulk polycrystalline arc-melted ingot under a high purity argon atmosphere with a linear speed of the rotating copper wheel of 25 ms−1 using an Edmund Bühler model SC melt spinner system [12]. From scanning electron microscopy (SEM) images it was determined that the as-solidified ribbons obtained had an average thickness of 15 ± 1 μm. The phase purities and crystal structures were determined by room
Results and discussion
Fig. 1 shows the indexed room temperature XRD pattern of Ni0.895Cr0.105MnGe1.05 ribbon flakes. Analysis of the XRD pattern revealed that the as-quenched ribbons crystallize into a single-phase with the Ni2In-type hexagonal structure. The calculated values of the lattice parameters a and c of the hexagonal structure at room temperature were found to be 4.086(1) Å and 5.392(1) Å, respectively, with c/a ratio ∼1.32. The degree of hexagonal distortion in this compound calculated using (1 − c/a
Conclusion
In conclusion, the MCE parameters, ΔSM and ΔTad, in rapidly solidified Ni0.895Cr0.105MnGe1.05 melt-spun ribbons were explored using direct and indirect measurements in magnetic field changes up to 10 T at the second order transition. The maximum values of the adiabatic temperature changes (ΔTadmax) and the magnetic entropy change (|ΔSMpeak|) near the Curie temperature (TC) were found to be ∼2.6 K (µoΔH = 10 T) and 4.4 J kg−1 K−1(µoΔH = 5 T), respectively. Both ΔTad and the isothermal
Acknowledgments
This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under Award No. DE-FG02-06ER46291 (SIU) and DE-FG02-13ER46946 (LSU). The work of Y. S. Koshkidko was supported by the National Science Center, Poland through the SONATA Program under Grant No. 2016/21/D/ST3/03435. J.L. Sánchez Llamazares acknowledges support from Laboratorio Nacional de Nanociencias y Nanotecnología (LINAN, IPICyT). C.F. Sánchez-Valdés is grateful to DMCU-UACJ for
References (30)
- et al.
J. Magn. Magn. Mater.
(2009) - et al.
J. Magn. Magn. Mater.
(1995) - et al.
Intermetallics
(2018) - et al.
J. Alloys Compd.
(2017) - et al.
Prog. Mater. Sci.
(2018) - et al.
Scr. Mater.
(2012) - et al.
J. Alloys Compd.
(2017) - et al.
J. Magn. Magn. Mater.
(2017) - et al.
J. Alloys Compd.
(2014) - et al.
Phys. Rev. Lett.
(1997)
Nature
Phys. Rev. B
Appl. Phys. Lett.
Appl. Phys. Lett.
Rep. Prog. Phys.
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