Magnetic Phases and Chirality Control in Magnetic Multiferroics Nd0.8Tb0.2Mn₂O₅ by the Neutron Scattering

Neutron diffraction study of Nd
_0.8
Tb
_0.2
Mn
₂
O
₅
single crystal has been performed using both non-polarized and polarized neutron diffraction. Low temperature set of magnetic satellites corresponding to two magnetic ordered phases witnesses about the magnetic phase separation. One of those phases with propagation vector
$k_{1} = (0.5\,\,0\,\,k_{z1})$
bears features of magnetic order in TbMn
₂
O
₅
with ordering temperature
$\text {TN} \approx 37$
K. Another one with propagation vector
$k_{2} = (0.5\,\,0\,\,k_{z2})$
and Neel temperature of
$\text {TN2} \approx 30$
K has a great similarity to magnetic order of NdMn
₂
O
₅
. Both of them are chiral at low temperatures. Difference in chiral domain population could be controlled by the external electric field of few kV/cm. Two additional magnetic phases with
$k_{3,4} = (0.5\,\,0\,\,k_{z3,4})$
were observed in the short intermediate temperature range 20–28 K. Significant temperature hysteresis of 6–8 K for all magnetic phases was observed in dependence of cooling/heating temperature evolution. Results are discussed in the frame of competing magnetic interactions.