C. Dhanasekhar

Low‐dimensional magnets, particularly 2D systems, offer a rich platform for realizing unconventional multiferroic mechanisms, especially when multiple polarization channels coexist. In the quasi‐2D antiferromagnet CrSbS ₃ , which crystallizes in the centrosymmetric orthorhombic space group Pnma and orders magnetically at T _N ≈ 90 K, two independent polarization mechanisms are uncovered. A weak spontaneous polarization (P ₁ ) emerges near T _E ≈ T _N at zero field, driven by partial Cr charge transfer. Synchrotron XRD refinements reveal anomalies in bond valences and average Cr─S bond length, XAS detects subtle modifications in local electronic states, and Raman spectroscopy uncovers anomalous phonon softening, indicating a charge‐transfer‐driven reconstruction of the lattice and phonon. In addition, second‐harmonic generation (SHG) measurements exhibit a clear enhancement below T _E , directly confirming inversion‐symmetry breaking and supporting the emergence of the spontaneous polarization P ₁ . Further, neutron diffraction reveals a C‐type antiferromagnetic structure described by the magnetic space group Pnm'a , which breaks inversion symmetry and induces an additional polarization (P ₂ ) under applied magnetic fields. Critical exponent analysis ( β ≈ 0.23(2)) highlights quasi‐2D magnetism. These results establish CrSbS ₃ as a rare high‐ T _c / T _N (∼90 K) type‐II multiferroic, where charge, spin, lattice, and phonon degrees of freedom cooperatively produce robust ferroic responses in a 2D framework.

Polymorph (spinel/ilmenite) composite nanofibers of nickel titanate (NTO) were prepared by a sol–gel assisted electrospinning process followed by pyrolysis using the styrene–acrylonitrile copolymer as a precursor at three different pyrolysis soaking temperatures (i.e. T = 773, 973, and 1173 K). The magnetic behavior of these composite NTO nanofibers was studied under isothermal and non-isothermal conditions in the temperature range of 20–300 K. The magnetic parameters such as coercivity (H_c), remanence (M_r), and saturation magnetisation (M_s) were found to be strongly dependent on T. The highest H_c and M_r were observed for NTO nanofibers developed at 973 K, which have a mosaic structured morphology with spinel and ilmenite NTO crystallite sizes of ∼39 nm and ∼24 nm, respectively. On the other hand, the highest M_s and switching field distribution were observed for mosaic structured NTO nanofibers having smaller crystallites (∼13 nm and 24 nm for spinel and ilmenite NTO, respectively, with high inter-particle distance and high porosity) developed at 773 K, which are also rich in spinel NTO content. The correlation between the variation in magnetic behavior and structural/morphological features of NTO nanofibers is useful for NTO-based soft magnetic and multiferroic applications.

CaBaCo ₄ O ₇ (CBCO) cobaltite shows a giant spin driven pyroelectric polarization below its ferrimagnetic transition temperature at 64 K. In the present study, we have investigated the structural, magnetic and electric polarization properties of light nonmagnetic Zn doped polycrystalline CaBaCo _3.97 Zn _0.03 O ₇ (CBCZO) cobaltite. Neutron powder diffraction studies on the CBCZO show that the Zn occupies the Co2 sites which lowers the strength of the magnetic interactions between the bitetrahedral cobalt c -axis chains. Further, we show that these chains act as magnetic clusters and causes the switching of the electric polarization. This study specifies that the ferrimagnetic–pyroelectric ground state of CBCO is very sensitive to the light non-magnetic doping and the results can be used to further understand the pyroelectric polarization switching properties of CBCO.