Related Experiment Video
Updated: Apr 19, 2026

08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
9.1K
Tuning structural instability toward enhanced magnetocaloric effect around room temperature in MnCo(1-x)Zn(x)Ge
D Choudhury1, T Suzuki1, Y Tokura2
1RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
Scientific Reports
|December 19, 2014
Summary
Researchers enhanced the magnetocaloric effect in MnCo(1-x)Zn(x)Ge alloys by utilizing magnetic-field-induced structural instability. This advancement is crucial for developing efficient, eco-friendly magnetic refrigeration technologies.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Thermodynamics
Background:
- The magnetocaloric effect (MCE) is a physical phenomenon where magnetic materials change temperature upon application or removal of a magnetic field.
- MCE is a promising basis for environmentally friendly magnetic refrigeration, offering an alternative to traditional gas compression systems.
- Optimizing MCE in materials is key to realizing practical magnetic refrigeration applications.
Purpose of the Study:
- To investigate the role of magnetic-field-induced structural instability in enhancing the magnetocaloric effect.
- To explore the effects of Zn substitution (x) on the structural and magnetic properties of MnCo(1-x)Zn(x)Ge alloys.
- To identify optimal compositions for high-performance magnetocaloric materials.
Main Methods:
- Synthesis and characterization of MnCo(1-x)Zn(x)Ge alloys with varying Zn concentrations (x = 0-0.05).
- Measurement of magnetocaloric effect, structural transitions, and magnetic properties.
- Analysis using Landau free-energy phenomenology to model structural phase diagrams.
Main Results:
- Increased Zn content (x) significantly lowers the martensitic transition temperature while maintaining the ferromagnetic transition near room temperature.
- A specific composition (x ≈ 0.03) exhibits a coupled structural and ferromagnetic transition during cooling, leading to an enhanced MCE.
- The study observed a magnetic-field-induced structural transition, correlating with the enhanced magnetocaloric effect.
Conclusions:
- Magnetic-field-induced structural instability plays a critical role in enhancing the magnetocaloric effect in MnCo(1-x)Zn(x)Ge alloys.
- The observed magnetocaloric effect is strongly dependent on the Zn concentration, highlighting the importance of precise compositional tuning.
- Understanding and exploiting magnetostructural coupling is essential for designing advanced magnetocaloric materials for efficient refrigeration.
Related Concept Videos
Ferromagnetism
3.6K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
3.6K
Paramagnetism
3.3K
Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...
3.3K
Types Of Superconductors
1.9K
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
1.9K
Magnetostatic Boundary Conditions
1.9K
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
1.9K
Potential Due to a Magnetized Object
897
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
The vector...
897
Magnetism
10.2K
Magnets are commonly found in everyday objects, such as toys, hangers, elevators, doorbells, and computer devices. Experimentation on these magnets shows that all magnets have two poles: one is labeled north (N) and the other south (S). Magnetic poles repel if they are alike and attract if unlike. Moreover, both poles of a magnet attract unmagnetized pieces of iron.
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
10.2K

