Related Experiment Video
Updated: Jun 4, 2026
07:03
Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
Multiferroic magnetoelectric fluorides: why are there so many magnetic ferroelectrics?
1Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK. jfs32@hermes.cam.ac.uk
Summary
Magnetic ferroelectric materials are not rare. This review highlights multiferroic magnetic fluorides, including K(3)Fe(5)F(15) and Pb(5)Cr(3)F(19) families, showing their prevalence and properties.
Area of Science:
- Materials Science
- Solid State Physics
- Crystallography
Background:
- Multiferroic materials exhibiting both magnetic and ferroelectric properties are of significant scientific interest.
- The perception that magnetic ferroelectrics are rare in nature is widespread but potentially inaccurate.
- Fluoride-based compounds represent a promising class for exploring multiferroic phenomena.
Purpose of the Study:
- To challenge the notion that magnetic ferroelectrics are uncommon.
- To provide a comprehensive review of multiferroic magnetic fluorides.
- To detail specific families of magnetic fluorides with piezoelectric and ferroelectric characteristics.
Main Methods:
- Literature review of existing research on multiferroic magnetic fluorides.
- Qualitative summary of main families of magnetic fluorides with piezoelectric and ferroelectric properties.
- Detailed discussion of the K(3)Fe(5)F(15) and Pb(5)Cr(3)F(19) families.
Main Results:
- Magnetic fluorides with piezoelectric and likely ferroelectric properties are more common than previously thought.
- Key structural and property characteristics of the K(3)Fe(5)F(15) family are presented.
- Key structural and property characteristics of the Pb(5)Cr(3)F(19) family are presented.
Conclusions:
- Multiferroic magnetic fluorides are a significant and accessible class of materials.
- The K(3)Fe(5)F(15) and Pb(5)Cr(3)F(19) families exemplify the potential of magnetic fluorides.
- Further research into magnetic fluorides can expand the landscape of multiferroic materials.
Related Concept Videos
01:31Ferromagnetism
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...
03:02Colors and Magnetism
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 eye.
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 eye.
01:30Paramagnetism
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...
01:31Magnetic Susceptibility and Permeability
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
01:26Diamagnetism
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.
01:27Magnetic Fields
A moving charge or a current creates a magnetic field in the surrounding space, in addition to its electric field. The magnetic field exerts a force on any other moving charge or current that is present in the field. Like an electric field, the magnetic field is also a vector field. At any position, the direction of the magnetic field is defined as the direction in which the north pole of a compass needle points.
A magnetic field is defined by the force that a charged particle experiences...
A magnetic field is defined by the force that a charged particle experiences...