  The present study reports on the structural and magnetic phase transitions in
Pr-doped polycrystalline Tb0.6Pr0.4MnO3, using high-resolution neutron powder
diffraction (NPD) collected at SINQ spallation source (PSI), to emphasize the
suppression of the sinusoidal magnetic structure of pure TbMnO3 and the
evolution to a collinear A-type antiferromagnetic ordering. The phase purity,
Jahn-Teller distortion, and one-electron bandwidth for eg orbital of Mn3+
cation have been calculated for polycrystalline Tb0.6Pr0.4MnO3, in comparison
to the parent materials TbMnO3 and PrMnO3, through the Rietveld refinement
study from X-ray diffraction data at room temperature. The
temperature-dependent zero field-cooled and field-cooled dc magnetization study
at low temperature down to 5 K reveals a variation in the magnetic phase
transition due to the effect of Pr3+ substitution at the Tb3+ site, which gives
the signature of the antiferromagnetic nature of the sample, with a weak
ferromagnetic component at low temperature induced by an external magnetic
field. The field-dependent magnetization study at low temperatures gives the
weak coercivity having the order of 2 kOe, which is expected due to canted-spin
arrangement or ferromagnetic nature of Terbium ordering. The NPD data for
Tb0.6Pr0.4MnO3 confirms that the nuclear structure of the synthesized sample
maintains its orthorhombic symmetry down to 1.5 K. Also, the magnetic
structures have been solved at 50 K, 25 K, and 1.5 K through the NPD study,
which shows A-type antiferromagnetic spin arrangement.
