Realization of magnetostructural coupling by modifying structural transitions in MnNiSi-CoNiGe system with a wide Curie-temperature window

Abstract

The magnetostructural coupling between structural and magnetic transitions leads to magneto-multifunctionalities of phase-transition alloys. Due to the increasing demands of multifunctional applications, to search for the new materials with tunable magnetostructural transformations in a large operating temperature range is important. In this work, we demonstrate that by chemically alloying MnNiSi with CoNiGe, the structural transformation temperature of MnNiSi (1200 K) is remarkably decreased by almost 1000 K. A tunable magnetostructural transformation between the paramagnetic hexagonal and ferromagnetic orthorhombic phase over a wide temperature window from 425 to 125 K is realized in (MnNiSi)1−x(CoNiGe)x system. The magnetic-field-induced magnetostructural transformation is accompanied by the high-performance magnetocaloric effect, proving that MnNiSi-CoNiGe system is a promising candidate for magnetic cooling refrigerant.

First-order magnetic phase transition in Pr2In with negligible thermomagnetic hysteresis

“…Exhibited by a broad variety of materials and systems that range from ionic solids to metals, semimetals, and semiconductors, FOMPTs are a vibrant area of research because their occurrence may lead to useful functionalities, such as giant magnetocaloric effect, giant magnetostriction, and colossal magnetoresistance [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. These phenomena often arise when magnetic (dis)order-order transitions occur in parallel with changes in the underlying crystal lattice, leading to magnetostructural transformations (MSTs), which are commonly associated with thermomagnetic hysteresis [1][2][3][4][5][6][7][8][9][10][11][12][13]. Cycling a material across a hysteretic MST results in energy losses [1] which are detrimental to energy conversion applications, solid-state caloric cooling being one example.…”

“…Cycling a material across a hysteretic MST results in energy losses [1] which are detrimental to energy conversion applications, solid-state caloric cooling being one example. Over the years, considerable research efforts have been dedicated to designing materials with MSTs where concurrent changes of magnetic and crystallographic sublattices occur with the smallest possible hysteresis [1][2][3][4][5][6][7][8][9][10][11][12].…”

Viable Materials with a Giant Magnetocaloric Effect

“…There are thousands of magnetocaloric publications, including hundreds of those mentioning a giant caloric effect, see Figure 2b. However, most considered materials are not economically viable, because they contain precious metals (Rh, Pd) [21,22,24], rare earth [12,[38][39][40][41], expensive germanium [42,43] or gallium [28,44], toxic elements [45][46][47][48][49][50][51], or hydrogen [52][53][54][55], which is released in a gas phase, see Figure 2c. Before 2005, a large MCE (exceeding that in metallic Gd) was claimed in precious FeRh [21,22], expensive Gd 5 Si 2 Ge 2 [28,[56][57][58][59][60][61][62][63][64][65][66][67][68] and related materials (GdGe 4 [69,70], GdSn 4 [71,72], Tb 5 Si 2 Ge 2 [73]), Heusler alloys…”

Tunable Martensitic Transformation and Magnetic Properties of Sm-Doped NiMnSn Ferromagnetic Shape Memory Alloys

“…This coupled transition is obtained around the MT temperature (T t ). These multifunctional properties show application in vast areas such as magnetic refrigeration, energy harvesting, magneto-mechanical devices and sensors [11][12][13][14]. The MCE is a magneto-thermodynamic phenomenon in which the temperature is changed in the material when exposed to an external non-constant magnetic field [15].…”