Temperature versus composition phase diagram and temperature evolution of structure and modulation of Ni2MnGa1-xInx single crystals
Introduction
The shape memory alloys of Ni–Mn-Ga system attracted significant attention because of their promising potential applications as actuators, sensors, micropumps or magnetic refrigerators [[1], [2], [3]]. These applications are related to magnetically induced reorientation (MIR) [4] and giant magnetic-field induced strain (MFIS) – up to 12% can be reached by appropriate alloying [[4], [5], [6], [7], [8]].
The properties of these materials are connected to the martensitic transformation, during which the high-temperature cubic phase (austenite) undergoes a transformation to the low-temperature phase with lower symmetry (martensite) [[9], [10], [11]]. In most cases the martensitic phase exhibits the structure modulation [10,12,13], however, the non-modulated Ni–Mn-Ga martensite has also been reported [4,6]. Depending on composition, one could observe additional pre-martensitic phase. Pre-martensitic transformation (austenite to pre-martensite) occurs at temperatures higher than martensitic transformation temperature (TM) and it is connected to the partial condensation of the transversal acoustic phonon branch [15,16]. As a consequence, the pre-martensite is a cubic phase exhibiting the structure modulation with the modulation vector .
Many works were published describing the behavior of martensitic transformation in Ni–Mn-Ga related alloys under various conditions. The critical temperatures of Ni–Mn-Ga based alloys are strongly dependent on alloying and composition. For example, the partial substitution of Mn with Ni atoms results in an increase of TM and a decrease of Curie temperature (TC) [17]. Contrary, substitution of Mn with Fe leads to a decrease of TM and to an increase of TC [18,19]. The alloying of Ni sites with Co increases the Curie temperature, but contrary to that this alloying decreases TM [19,20]. Replacing Ga or Mn site with Cu causes TM increase [19,21]. Recently, Armstrong et al. [22] published the study dealing with the systematic trends of transformation temperatures in Ni–Mn-Ga-Fe-Cu alloys which shows how the individual element concentrations influence TM and TC.
In this paper, the effects of alloying of Ga sites with In atoms is studied. Several articles dealing with In alloying were already published [[23], [24], [25], [26], [27], [28]]. The articles [[23], [24], [25],27] showed the study of Co and In alloyed Ni2MnGa in the purpose of an examination of magnetocaloric properties. Khan et al. [26] studied systematically the behavior of the physical properties with respect to indium content. Glavatskyy et al. [28] studied the Ni2MnGa compound under the various alloying of Si, In, Co and Fe. All these papers showed that indium alloying decreases the critical temperatures. However, it needs to be pointed out that these works were done on polycrystalline samples. A good single crystal is the prerequisite for any significant MIR effect [10,14,29], since the grain boundaries can block the motion of twin boundaries. A single crystal is also necessary for precise determination of the structure, since MIR and consequential twinning could lead to a quite complex splitting of Bragg reflections after the martensitic transformation. The detailed single crystal X-ray diffraction measurements presented here were performed within a wide temperature range and allowed us the precise determination of the structure and the description of modulation changes with respect to the temperature.
Section snippets
Experimental setup
For the preparation of single crystals with a various indium content we used a similar procedure as is described in our previously published work [29]. Polycrystalline precursors were prepared in a monoarc furnace from 5 N Ni, 7 N Ga, 3N5 Mn and 5 N In pellets in Ar atmosphere of 0.3 bar. To compensate the evaporation during the arc melting we added three extra weight percents of Mn and Ga, in advance. The evaporation was not an important issue in subsequent single crystal growth by Bridgman
Samples characterization
The DSC measurements on as grown and annealed single crystals were performed to obtain the position of B2‘→L21 transition. The result for the sample Ni2MnGa0.95In0.05 for two measurement cycles is shown in Fig. 1a. For Ni2MnGa0.95In0.05 sample B2‘→L21 transition occurs around 798 °C. The position of the transition seems independent on the heat treatment procedure or measurement cycle, since there is no significant shift of the data with respect to a temperature. From the results measured on Ni2
Conclusions
A series of single crystalline Ni2MnGa1-xInx samples with different indium content were prepared by Bridgman method. The chemical composition of samples was measured by EDX and XRF. Widely used 48 h of homogenization annealing is not enough to homogenize indium distribution in the samples. After 120 h of homogenization annealing at 1000 °C the In distribution is well homogenized.
The measurement of temperature dependence of the electrical resistivity and the magnetisation was performed to obtain
CRediT authorship contribution statement
Petr Cejpek: Investigation, Conceptualization, Formal analysis, Writing - original draft, Writing - review & editing, Visualization. Petr Doležal: Investigation. Petr Opletal: Investigation. Jaroslav Valenta: Investigation. Kristina Vlášková: Investigation. Milan Dopita: Writing - original draft, Writing - review & editing, Supervision.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This project was supported by Grant Agency of Charles University (GAUK), project No. 244217. We want to acknowledge the financial support from the project NanoCent - Nanomaterials Centre for Advanced Applications, Project No. CZ.02.1.01/0.0/0.0/15_003/0000485, financed by European Regional Development Fund (ERDF). Samples preparation and measurements were performed in MGML (mgml.eu), which is supported within the program of Czech Research Infrastructures (Project No. LM2018096, financed by
References (43)
- et al.
Sensing strain with Ni-Mn-Ga
Sensor. Actuator. A
(2018) - et al.
Magnetocaloric effect: from materials research to refrigeration devices
Prog. Mater. Sci.
(2018) - et al.
Oriented single crystals of Ni–Mn–Ga with very low switching field
J. Cryst. Growth
(2012) - et al.
Structure and microstructure of Ni-Mn-Ga single crystal exhibiting magnetic shape memory effect analysed by high resolution X-ray diffraction
Acta Mater.
(2016) - et al.
Commensurate and incommensurate 5M modulated crystal structures in Ni-Mn-Ga martensitic phases
Acta Mater.
(2007) - et al.
Tuning the magnetic and magnetocaloric properties of austenitic Ni-Mn-(In,Sn) Heuslers
Scripta Mater.
(2019) - et al.
Transformation temperatures and magneto plasticity of Ni–Mn–Ga alloyed with Si, In, Co or Fe
Scripta Mater.
(2006) - et al.
Rapid floating zone growth of Ni2MnGa single crystals exhibiting magnetic shape memory functionality
J. Alloys Compd.
(2019) - et al.
Effect of atomic order on the martensitic transformation of Ni-Fe-Ga alloys
Scripta Mater.
(2006) - et al.
Chemical ordering in Ni-Mn-Ga Heusler alloys
Scripta Mater.
(1999)
Effect of chemical ordering annealing on martensitic transformation and superelasticity in polycrystalline Ni–Mn–Ga microwires
J. Alloys Compd.
Standard enthalpies of formation of selected Ni2YZ Heusler compounds
J. Alloys Compd.
Ni–Mn–Ga high-temperature shape memory alloys
Sci. Eng. A
Effect of hydrostatic pressure on martensitic transformation in a ferromagnetic shape memory alloy Ni2MnGa
J. Alloys Compd.
Magnetocaloric and barocaloric effects associated with two successive magnetostructural transformations in Ni55.5Mn17.8Ga26.7 alloy
J. Alloys Compd.
Characterization of a high resolution solid state micropump that can be integrated into microfluidic systems
Microfluidic. Nanofluidics
Magnetic Shape Memory Phenomena
Large magnetic-field-induced strains in Ni2MnGa single crystals
Appl. Phys. Lett.
12% magnetic field-induced strain in Ni-Mn-Ga-based non-modulated martensite
Appl. Phys. Lett.
Magneto-mechanical cycling and modeling the external stress effect on the magnetic-field-controlled strain response in Ni-Mn-Ga
J. Phys. IV Fr.
Cited by (3)
Dependence of martensite transformation temperature on magnetic field in Ni<inf>2</inf>MnGa and Ni<inf>2</inf>MnGa<inf>0.95</inf>In<inf>0.05</inf> single crystals
2022, Journal of Alloys and CompoundsCitation Excerpt :Then the annealing continued for 2 days at 1123 K, which was followed by quenching into water to achieve a high degree of L21 order. The whole preparation procedure was described in more detail in references [19,38]. The ingots were oriented with Laue method and manufactured to the shape of small parallelepiped samples with their faces along the crystallographic planes {100} (in austenitic phase).
Synthesis and characterisation of Fe-substituted Ni<inf>50</inf>Mn<inf>25</inf>Fe<inf>x</inf>Ga<inf>25-x</inf> single crystals—Development of the phase transformations with Fe content
2022, Journal of Alloys and CompoundsCitation Excerpt :A second approach consists of partial substitution of Ni2MnGa by constituents or/and other transition and/or main-block elements. Many studies have been published, most often revealing a decrease of TM with alloying, e.g., [34–39]. Only a few substitutions shift TM to/above room temperature, e.g., Co or Fe doped Ni2MnCoxGa1-x and Ni2MnFexGa1-x [35], Mn and Fe doping in Ni2Mn1.08Fe0.04Ga0.88 [40], and Mn-Ga content variation in Ni2Mn1+xGa1-x [41].