#multiferroic

Important step for practical application of advanced material

Toyohashi University of Technology has developed a novel liquid process for fabrication of an affordable multiferroic nanocomposite film in collaboration with Japan Fine Ceramics Center, National Institute of Technology Ibaraki College, International Iberian nanotechnology Laboratory, Chang'an university and University of Erlangen-Nuremberg. The multiferroic material obtained by the novel process possesses strong correlation between the electric and the magnetic properties, thus various applications such as low-power-consumption large-volume memory, spatial light modulator, and unique sensors, etc. are expected in the future.

Multiferroic materials combine electrical (ferroelectric) and magnetic (ferromagnetic) properties and have a strong correlation between these properties (exhibit a magnetoelectric effect), and their development is expected to realize more versatile and higher performance next-generation electrical and magnetic devices. In recent years, several methods of production of multiferroic films exhibiting large magnetoelectric properties have been reported. However, these processes require large and extraordinary expensive vacuum devices, making them impractical for fabricating materials with a large area in particular. As a result, multiferroic materials have only been used in a very limited range of applications.

With this background, the research team developed a process for producing a material with advanced multiferroic properties by combining several liquid-phase methods that are relatively inexpensive and simple.

Neutrons help demystify multiferroic materials

Materials used in electronic devices are typically chosen because they possess either special magnetic or special electrical properties. However, an international team of researchers using neutron scattering recently identified a rare material that has both.

In their paper published in Advanced Materials, the team, including researchers from the Department of Energy's (DOE's) Oak Ridge National Laboratory (ORNL), illustrates how this unique marriage is achieved in the multiferroic material BiMn3Cr4O12. Many materials are known for just one characteristic magnetic or electrical property, or for having the ability to change shape, but multiferroics contain some combination of these attributes.

Multiferroics are typically divided into two distinct categories: conventional (type-1) and unconventional (type-2). Conventional multiferroics are predominantly controlled by electricity and exhibit weak interactions with magnetism. Conversely, unconventional multiferroics are driven by magnetism and exhibit strong electrical interactions.

Research on bismuth ferrite could lead to new types of electrical devices

Electrical devices in use today use conductive materials to guide electrons where they are needed. These materials must be fastened in place and insulated in order to keep the electricity on the right path. New research from the University of Arkansas makes a significant step toward a new kind of electrical device, which would use the natural properties of materials like bismuth ferrite, along with a different type of current, to send electricity quickly through smaller, denser circuits.

Sergey Prosandeev, a research professor in the Department of Physics, worked with Yurong Yang, research associate professor; Charles Paillard, post doctoral fellow; and Laurent Bellaiche, Distinguished Professor. Their results are published in the journal npj Computational Materials.

Using the Arkansas High Performance Computing Center, these researchers created simulations of bismuth ferrite, a synthetic, crystalline material. Bismuth ferrite is "multiferroic," which means that it has regions, or domains, in which the molecules making up its crystalline structure exhibit a consistent pattern of electric polarization, magnetization and shifting of charged ions. The boundaries between these regions are called domain walls. These walls are two-dimensional and very narrow—they are measured in tenths of nanometers.

Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They have fascinating properties such as magnetic (electric) field-controlled ferroelectric (ferromagnetic) properties and can be used in novel technological applications such as fast-writing, power-saving, and nondestructive data storage. However, because multiferroicity is typically observed at low temperatures, it is highly desirable to develop multiferroic materials that can be observed at room temperature.

GaxFe2-xO3, or GFO for short, is a promising room-temperature multiferroic material because of its large magnetization. GFO thin films have already been successfully fabricated, and their polarization switching at room temperature has been demonstrated. However, their ferroelectric and ferromagnetic properties must be controlled to realize better magnetoelectric properties and applications of GFO films. In order to control these properties, it is essential to understand the relationship between the constituent composition at each cation site and the original character.

'Atomic sandwiches' could make computers 100X greener

Researchers have engineered a material that could lead to a new generation of computing devices, packing in more computing power while consuming a fraction of the energy that today's electronics require.

Known as a magnetoelectric multiferroic material, it combines electrical and magnetic properties at room temperature and relies on a phenomenon called "planar rumpling."

The new material sandwiches together individual layers of atoms, producing a thin film with magnetic polarity that can be flipped from positive to negative or vice versa with small pulses of electricity. In the future, device-makers could use this property to store digital 0's and 1's, the binary backbone that underpins computing devices.

"Before this work, there was only one other room-temperature multiferroic whose magnetic properties could be controlled by electricity," said John Heron, assistant professor in the Department of Materials Science and Engineering at the University of Michigan, who worked on the material with researchers at Cornell University. "That electrical control is what excites electronics makers, so this is a huge step forward."

New multiferroic materials from building blocks

A research group in Japan successfully developed room temperature multiferroic materials by a layer-by-layer assembly of nanosheet building blocks. Multiferroic materials are expected to play a vital role in the development of next-generation multifunctional electronic devices.

A research group led by principal investigator Minoru Osada and fellow Takayoshi Sasaki, International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), successfully developed room temperature multiferroic materials by a layer-by-layer assembly of nanosheet building blocks. Multiferroic materials are expected to play a vital role in the development of next-generation multifunctional electronic devices.

The design of new multiferroics, or materials that display both ferroelectricity and ferromagnetism, is of fundamental importance for new electronic technologies. However, the co-existence of ferroelectricity and magnetic order at room temperature in single compounds is rare, and heterostructures with such multiferroic properties have only been made with complex techniques (such as pulsed-laser deposition and molecular beam epitaxy).

Crystal, magnetic structure of multiferroic hexagonal manganite

Ever since Curie conjectured on "the symmetry in physical phenomena, symmetry of an electric field and a magnetic field," it has long been a dream for material scientists to search for this rather unusual class of material exhibiting the coexistence of magnetism and ferroelectricity in a single compound known as a multiferroic compound.

Multiferroic materials are a class of crystalline material which exhibit a number of unique properties, in which at least two order parameters exist simultaneously; ferro- (or antiferro-) magnetic, ferroelectric and ferroelastic degrees of freedom. These properties give rise to a number of useful and practical applications such as memory devices and sensors. Even though multiferroic materials are relatively commonplace much is still not known about their molecular make-up and properties. This article presents an extended and comprehensive review of the structure and multiferroic properties of the hexagonal rare-earth manganite RMnO3, in which there are ferroelectric and magnetic orders. Strong interaction between these orders causes a series of interesting properties of multiferroics. The review describes multiferroics with antiferromagnetic and ferroelectric orders. A commentary about this paper has also been commissioned.