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).
Seeking to develop
room-temperature multiferroics, the research group utilized a new chemical
design for artificial multiferroic thin films using two-dimensional oxide
nanosheets as building blocks. This approach enables engineering the interlayer
coupling between the ferromagnetic and ferroelectric orders, as demonstrated by
artificial superlattices composed of ferromagnetic Ti0.8Co0.2O2 nanosheets and
dielectric perovskite-structured Ca2Nb3O10 nanosheets. The (Ti0.8Co0.2O2/Ca2Nb3O10/Ti0.8Co0.2O2)
superlattices exhibit the multiferroic effects at room temperature, which can
be modulated by tuning the interlayer coupling (i.e., the stacking sequence).
This study opens a pathway
to create new artificial materials with tailored multiferroic properties. In
addition, the successful development of room temperature multiferroic nanofilms
may lead to their application to new memory devices, taking advantage of their
multifunctionality and low-voltage operation.