40,029 research outputs found
Coexistence of coupled magnetic phases in epitaxial TbMnO3 films revealed by ultrafast optical spectroscopy
Ultrafast optical pump-probe spectroscopy is used to reveal the coexistence
of coupled antiferromagnetic/ferroelectric and ferromagnetic orders in
multiferroic TbMnO3 films through their time domain signatures. Our
observations are explained by a theoretical model describing the coupling
between reservoirs with different magnetic properties. These results can guide
researchers in creating new kinds of multiferroic materials that combine
coupled ferromagnetic, antiferromagnetic and ferroelectric properties in one
compound.Comment: Accepted by Appl. Phys. let
Semimetal-semiconductor transition and giant linear magnetoresistances in three-dimensional Dirac semimetal Bi0.96Sb0.04 single crystals
Three-dimensional (3D) Dirac semimetals are new quantum materials and can be
viewed as 3D analogues of graphene. Many fascinating electronic properties have
been proposed and realized in 3D Dirac semimetals, which demonstrates their
potential applications in next generation quantum devices. Bismuth-antimony
Bi1-xSbx can be tuned from a topological insulator to a band insulator through
a quantum critical point at x ~ 4%, where 3D Dirac fermions appear. Here, we
report on a magnetotransport study of Bi1-xSbx at such a quantum critical
point. An unusual magnetic-field induced semimetal-semiconductor phase
transition was observed in the Bi0.96Sb0.04 single crystals. In a magnetic
field of 8 T, Bi0.96Sb0.04 single crystals show giant magnetoresistances of up
to 6000% at low-temperature, 5 K, and 300% at room-temperature, 300 K. The
observed magnetoresistances keep linear down to approximate zero-field when the
temperature is below 200 K. Our experimental results are not only interesting
for the fundamental physics of 3D Dirac semimetals, but also for potential
applications of 3D Dirac semimetals in magnetoelectronic devices.Comment: 9 pages, 3 figure
- …