We report a magnetic state in GaV 4 Se 8 which emerges exclusively in samples with mesoscale polar domains and not in polar monodomain crystals. It is manifested by a sharp anomaly in the magnetic susceptibility and the magnetic torque, distinct from other anomalies observed also in polar mono-domain samples upon transitions between the cycloidal, the Néel-type skyrmion lattice and the ferromagnetic states. We ascribe this additional transition to the transformation of distinct magnetic textures, confined to polar domain walls (DW), to the ferromagnetic (FM) state. The emergence of these DW-confined magnetic states is likely driven by the mismatch of different spin spirals, hosted by the adjacent domains. A clear anomaly in the magneto-current indicates that the DWconfined magnetic states also have strong contributions to the magnetoelectric response. We expect polar DWs to commonly host such confined magnetic edge states and, thus, offer a fertile ground to explore novel forms of magnetism.

A low band gap ferroelectric material with a sizable polarization at ambient conditions would constitute an ideal photovoltaic material to harvest solar energy because of its efficient polarization-driven charge carrier separation. We achieve this elusive goal by codoping a Jahn–Teller Mn3+ and Nb5+ pair for two Ti4+ ions in ferroelectric BaTiO3. Representing a charge-neutral dipole doping, this approach achieves for the first time a bulk ferroelectric oxide with the lowest band gap of 1.66 eV with a sizable polarization of nearly 70% of BaTiO3. We contrast this with the analogous system with Mn3+ replaced by the non-Jahn–Teller Fe3+ (3d5) ion, which even at a much lower level of doping reduces the polarization to 25% without reducing the band gap significantly, establishing the efficacy of the present strategy.

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Pyro-current measurements have been widely used to study ferroelectric properties in multiferroic materials. However, determination of intrinsic polarization by this method is not straightforward because of leakage current and trapped charge carriers. Here, we demonstrate the formation of internal electric field due to thermally stimulated charge carriers and its influence on ferroelectric polarization in a polycrystalline sample of the well known multiferroic TbMnO 3 . While an electric field (E ext ) poling across the ferroelectric transition (T C ∼ 26 K) is essential to obtain depolarization current at T C , the sample poled only in the paraelectric state (T pole = 130 − 50 K) also exhibits a pyro-current peak at T C but with the same polarity (− I pyro ) as that of the external field (− E ext ).We demonstrate that these unusual behavior of pyro-current are caused by a positive internal electric field (+ E int ) which in turn is created by thermally stimulated free charge carriers during the poling process in the paraelectric state. We also show that a combination of DC-biased current and pyro-current measurements is a promising method to study the intrinsic ferroelectric properties in multiferroic materials.