Synopsis: Multiferroic Surprise

Electric and magnetic polarization are spontaneously produced in an unlikely material—one with a highly symmetric crystal structure.
Synopsis figure
X. Wang et al., Phys. Rev. Lett. (2015)

Multiferroics are materials that inherently exhibit both magnetic and electric polarizations, making them highly prized for spintronic and other magnetoelectric applications. Multiferroicity typically derives from asymmetry in a material’s crystal structure. A new report, however, finds multiferroic behavior in a so-called cubic perovskite, which is highly symmetric. The team explains their unexpected results as arising from a novel interaction between different magnetic ions.

In a multiferroic material, the magnetic polarization is usually produced by transition metal ions (like iron and nickel), while the electric polarization (or ferroelectric effect) often relies on ions that shift position through interactions with their neighbors. These shifts can produce an electric polarization, but only if the crystal structure lacks an inversion center around which the crystal is symmetric.

Cubic crystals have an inversion center, so they are not expected to be multiferroic. But if the magnetization within the cubic material is asymmetric, then it may be possible to magnetically induce a ferroelectric effect. Youwen Long of the Beijing National Laboratory for Condensed Matter Physics in China and his colleagues investigated a cubic perovskite (LaMn3Cr4O12). The material’s two transition metal ions, manganese and chromium, exhibit magnetic spin ordering along the same direction in the lattice, and this spin pattern lacks an inversion center. When the researchers lowered the temperature to 50 K (at which point the material becomes fully magnetized), they detected electric polarization, suggesting a connection between the material’s magnetism and ferroelectricity. The researchers ruled out previous multiferroic models and instead performed calculations that showed the spin-orbit coupling between the different magnetic ions could produce the electric polarization.

This research is published in Physical Review Letters.

–Michael Schirber


Features

More Features »

Announcements

More Announcements »

Subject Areas

MagnetismMaterials Science

Previous Synopsis

Chemical Physics

Seeing a Bond’s Polarity

Read More »

Related Articles

Synopsis: A New Quantum Spin Liquid Candidate
Magnetism

Synopsis: A New Quantum Spin Liquid Candidate

Neutron scattering experiments reveal signatures of an exotic phase of matter in the pyrochlore magnet Ce2Zr2O7. Read More »

Focus: Two Types of Cooling Require Different Designs
Materials Science

Focus: Two Types of Cooling Require Different Designs

Keeping food cold is thermodynamically different from cooling a hot circuit element—a distinction that is accounted for in the design of a new thermoelectric cooler. Read More »

Focus: <i>Video</i>—Tunable Origami
Mechanics

Focus: Video—Tunable Origami

A folding pattern produces a metamaterial with properties that can be tuned over a wide range. Read More »

More Articles