2 research outputs found
Phase Transformation-Induced Tetragonal FeCo Nanostructures
Tetragonal FeCo nanostructures are
becoming particularly attractive
because of their high magnetocrystalline anisotropy and magnetization
achievable without rare-earth elements, . Yet, controlling their metastable
structure, size and stoichiometry is a challenging task. In this study,
we demonstrate AuCu templated FeCo shell growth followed by thermally
induced phase transformation of AuCu core from face-centered cubic
to L1<sub>0</sub> structure, which triggers the FeCo shell to transform
from the body-centered cubic structure to a body-centered tetragonal
phase. High coercivity, 846 Oe, and saturation magnetization, 221
emu/g, are achieved in this tetragonal FeCo structure. Beyond a critical
FeCo shell thickness, confirmed experimentally and by lattice mismatch
calculations, the FeCo shell relaxes. The shell thickness and stoichiometry
dictate the magnetic characteristics of the tetragonal FeCo shell.
This study provides a general route to utilize phase transformation
to fabricate high performance metastable nanomagnets, which could
open up their green energy applications
Room Temperature Multiferroicity of Charge Transfer Crystals
Room temperature multiferroics has been a frontier research field by manipulating spin-driven ferroelectricity or charge-order-driven magnetism. Charge-transfer crystals based on electron donor and acceptor assembly, exhibiting simultaneous spin ordering, are drawing significant interests for the development of all-organic magnetoelectric multiferroics. Here, we report that a remarkable anisotropic magnetization and room temperature multiferroicity can be achieved through assembly of thiophene donor and fullerene acceptor. The crystal motif directs the dimensional and compositional control of charge-transfer networks that could switch magnetization under external stimuli, thereby opening up an attractive class of all-organic nanoferronics