Public Abstract

DE-FG02-06ER46291: Phase Transitions and Physical Behaviors in Metastable Multicaloric Materials

Award Status: Active

Institution: Board of Trustees Southern Illinois University, Carbondale, IL
UEI: Y28BEBJ4MNU7
DUNS: 939007555

Most Recent Award Date: 09/22/2025
Number of Support Periods: 20
PM: Chen, Shawn

Current Budget Period: 07/01/2025 - 05/31/2026
Current Project Period: 07/01/2025 - 05/31/2028
PI: Talapatra, Saikat

Supplement Budget Period: N/A

Public Abstract

Phase Transitions and Physical Behaviors in Metastable Multicaloric Materials Shane Stadler, Louisiana State University (PI) Saikat Talapatra, Southern Illinois University (PI) A wide variety of novel and useful physical behaviors occur in materials that undergo transitions in which there is a simultaneous transformation in crystalline structure and magnetic state. Such a transformation is called a magnetostructural transition, and can be driven by magnetic field, temperature, strain, or pressure. These transitions can result in dramatic changes in material properties, including magnetic configuration, electronic state, crystal structure and cell volume, transport properties, and electronic structure, and often lead to novel physical behaviors such as giant magnetoresistance, asymmetric magnetoresistive switching, ferromagnetic shape memory effects, giant anomalous Hall effects, and bulk exchange bias. In this project, we are primarily interested magnetostructural transitions driven by magnetic field or hydrostatic pressure that generate a change in temperature of the material. Such solid-state caloric materials have applications in solid-state cooling, the burgeoning field that is driving promising new refrigeration technologies which are predicted to be more energy efficient and environmentally friendly than their conventional, vapor-compression-based predecessors. Our focus is on materials in which caloric effects are generated by magnetostructural transitions driven by magnetic field, or magnetocaloric effects, and/or driven by pressure, i.e., barocaloric effects. In some of the systems we will investigate, the magnetostructural transition simultaneously generates two or more types of caloric effects, and such materials are called multicaloric materials. In this collaborative effort between Louisiana State University and Southern Illinois University, we will study phase transitions and related physical behaviors in four classes of materials that generate magnetocaloric and/or barocaloric effects near room temperature: (i) All-d-metal Heusler alloys X₂YX starting with new, theoretically-predicted materials; (ii) Theoretically-predicted MM¢X compounds (M/M¢ = metal, X = main-group element) which undergo magnetic and structural phase transitions; (iii) Isoeletronically substituted Mn-based antiperovskites Mn₆₀X₂₀C₂₀ (X = Zn, Ga, Ge, Sn) synthesized through high-energy ball milling (HEBM); and (iv) Cr_xTe_y-based two-dimensional van der Waals ferromagnets. These materials all exhibit a variety of magnetic and structural transitions that lead to novel physical behaviors, and we will investigate the effects of doping, synthesis methods, and applied hydrostatic pressure on their phase transitions, and the solid-state caloric effects they generate. The objectives of this project are the following: (i) to experimentally realize (synthesize) new theoretically-predicted all-d-metal Heusler and MM¢X compounds and investigate their magnetostructural and solid-state caloric properties; (ii) to explore the effects of isoelectronic substitution on the magnetic and structural behaviors of Mn₆₀Ga₂₀C₂₀ compounds and investigate their magnetocaloric properties, and (iii) to investigate transport properties, phase transitions, and magnetocaloric properties of Cr_xTe_y-based, two-dimensional ferromagnets. The scientific outcomes include: (i) the discovery and development of new magnetocaloric and multifunctional materials; (ii) a deeper understanding of the physics of the phase transitions responsible for multicaloric and multifunctional behaviors; (iii) the observations of new physical phenomena in metastable alloy phases; and (iv) the establishment of connections between high-throughput theoretical predictions of new solid-state caloric materials and their corresponding experimental realizabilities: their synthesis, discovery, and physical behaviors. The discovery of a practical and effective solid-state refrigeration material will lead to more efficient cooling systems, operating from near room temperature to cryogenic ranges. The impact of this could be profound: it would be a significant step toward energy independence, national security, and a cleaner global environment, as cooling is one of the world’s most energy-demanding technologies.

Phase Transitions and Physical Behaviors in Metastable Multicaloric Materials

Shane Stadler, Louisiana State University (PI)

Saikat Talapatra, Southern Illinois University (PI)

A wide variety of novel and useful physical behaviors occur in materials that undergo transitions in which there is a simultaneous transformation in crystalline structure and magnetic state. Such a transformation is called a magnetostructural transition, and can be driven by magnetic field, temperature, strain, or pressure. These transitions can result in dramatic changes in material properties, including magnetic configuration, electronic state, crystal structure and cell volume, transport properties, and electronic structure, and often lead to novel physical behaviors such as giant magnetoresistance, asymmetric magnetoresistive switching, ferromagnetic shape memory effects, giant anomalous Hall effects, and bulk exchange bias. In this project, we are primarily interested magnetostructural transitions driven by magnetic field or hydrostatic pressure that generate a change in temperature of the material. Such solid-state caloric materials have applications in solid-state cooling, the burgeoning field that is driving promising new refrigeration technologies which are predicted to be more energy efficient and environmentally friendly than their conventional, vapor-compression-based predecessors.

Our focus is on materials in which caloric effects are generated by magnetostructural transitions driven by magnetic field, or magnetocaloric effects, and/or driven by pressure, i.e., barocaloric effects. In some of the systems we will investigate, the magnetostructural transition simultaneously generates two or more types of caloric effects, and such materials are called multicaloric materials.

In this collaborative effort between Louisiana State University and Southern Illinois University, we will study phase transitions and related physical behaviors in four classes of materials that generate magnetocaloric and/or barocaloric effects near room temperature: (i) All-d-metal Heusler alloys X₂YX starting with new, theoretically-predicted materials; (ii) Theoretically-predicted MM¢X compounds (M/M¢ = metal, X = main-group element) which undergo magnetic and structural phase transitions; (iii) Isoeletronically substituted Mn-based antiperovskites Mn₆₀X₂₀C₂₀ (X = Zn, Ga, Ge, Sn) synthesized through high-energy ball milling (HEBM); and (iv) Cr_xTe_y-based two-dimensional van der Waals ferromagnets. These materials all exhibit a variety of magnetic and structural transitions that lead to novel physical behaviors, and we will investigate the effects of doping, synthesis methods, and applied hydrostatic pressure on their phase transitions, and the solid-state caloric effects they generate.

The objectives of this project are the following: (i) to experimentally realize (synthesize) new theoretically-predicted all-d-metal Heusler and MM¢X compounds and investigate their magnetostructural and solid-state caloric properties; (ii) to explore the effects of isoelectronic substitution on the magnetic and structural behaviors of Mn₆₀Ga₂₀C₂₀ compounds and investigate their magnetocaloric properties, and (iii) to investigate transport properties, phase transitions, and magnetocaloric properties of Cr_xTe_y-based, two-dimensional ferromagnets.

The scientific outcomes include: (i) the discovery and development of new magnetocaloric and multifunctional materials; (ii) a deeper understanding of the physics of the phase transitions responsible for multicaloric and multifunctional behaviors; (iii) the observations of new physical phenomena in metastable alloy phases; and (iv) the establishment of connections between high-throughput theoretical predictions of new solid-state caloric materials and their corresponding experimental realizabilities: their synthesis, discovery, and physical behaviors.

The discovery of a practical and effective solid-state refrigeration material will lead to more efficient cooling systems, operating from near room temperature to cryogenic ranges. The impact of this could be profound: it would be a significant step toward energy independence, national security, and a cleaner global environment, as cooling is one of the world’s most energy-demanding technologies.