Related Experiment Video
Updated: Jun 7, 2025
07:42
Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains
Published on: July 20, 2022
2.6K
Magnetocaloric effect in a high-spin ferromagnetic molecular cluster
Eleftheria Agapaki1, Emmanouil K Charkiolakis2, Gary S Nichol1
1EaStCHEM School of Chemistry, The University of Edinburgh, Edinburgh, Scotland, United Kingdom.
Frontiers in Chemistry
|November 15, 2024
Summary
Researchers synthesized a novel mixed-valence manganese cluster with ferromagnetic properties. This discovery shows potential for applications in cryogenic refrigeration due to its magnetocaloric effect.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Magnetochemistry
Background:
- Manganese clusters are of interest for their unique magnetic properties.
- Developing new materials for cryogenic applications is crucial.
Purpose of the Study:
- To synthesize and characterize a novel mixed-valence manganese cluster.
- To investigate the magnetic properties and potential applications of the new cluster.
Main Methods:
- Reaction of MnCl2·4H2O with (1-methyl-1H-imidazol-2-yl)methanol and 1,3-propanediol in acetonitrile.
- Magnetic susceptibility, magnetization, and heat capacity measurements.
- Structural analysis of the resulting [Mn20] cationic cluster.
Main Results:
- Formation of a [Mn20] mixed-valence cationic cluster with [MnIICl4] counter anions.
- The cluster contains two linked [MnIII6MnII4] supertetrahedra with mixed oxidation states.
- Predominant ferromagnetic correlations observed, leading to a spin ground state of s = 22.
Conclusions:
- The synthesized manganese cluster exhibits significant ferromagnetic behavior.
- The compound shows potential for applications in magnetocaloric effect and cryogenic refrigeration.
Related Concept Videos
01:31Ferromagnetism
2.4K
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...
2.4K
03:02Colors and Magnetism
11.5K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.5K
01:30Paramagnetism
2.5K
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...
2.5K
01:26Diamagnetism
2.4K
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
2.4K
01:23Atomic Nuclei: Nuclear Relaxation Processes
630
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
630
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
950
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
950