Research

10.  Single-Domain Freestanding Nanomembrane 

While the high epitaxial-strain was found to strongly detriment the spin-cycloid nature of BiFeO3 thin films, the strong substrate clamping limited efficient ferroelastic-ferroelectric switching. In this context, we successfully fabricated large-area and crack-free all-monodomain BiFeO3 free-standing membrane, with efficient electric field switching (>50%) and robust bulk-like single spin-cycloid. 

P. Pal et al. (Under Review)

9.  Direct Imaging of Berry Curvature domains 

The discovery of anomalous Hall effect (AHE) in noncollinear antiferromagnets has opened a plethora of promising opportunities in antiferromagnetic devices. The key challenges limiting their full potential are (1) high-quality epitaxial thin-film growth and (2) the understanding of Berry curvature domain physics. 

We successfully grew Mn3NiN single-crystal epitaxial thin film. We probe the Berry curvature associated with antiferromagnetic Γ4g domains using high-resolution Sagnac MOKE microscopy. 

Y. Yao,†  P. Pal † et al. arXiv: 2410.02990 (2025). (Equal) (under revision in Science Advances)

8. Symmetry-Designed Single Domain Spin Cycloid

Deterministic control of coupled ferroelectric and antiferromagnetic orders remains a central challenge in multiferroics, limiting their integration into functional magnetoelectrics and magnonic-devices. We show that anisotropic-compressive in-plane strain stabilizes a single antiferromagnetic domain with unique spin-cycloid vector, by breaking the symmetry of the (111)pc plane. Epitaxial BiFeO3 films grown on orthorhombic NdGaO3 (011)o [(111)pc] substrates impose the required anisotropic in-plane strain and stabilizes single antiferromagnetic domain. 

P. Pal et al. arXiv: 241022447 (2025).

7. Stability of Ising ↑↑↓↓ Ordering 

Can cationic disorder lead to magnetic ordering?

We found surprising stability of the Ising ↑↑↓↓ antiferromagnetic order in Ca3CoMnO6 on cationic disorder, with a strong nonmonotonic dependence. Using both theory and experiments, we provide detailed observations and understanding of such unique phenomenon.

P. Pal et al. Phys. Rev. B  (2025).

6. What Drives Magnetic Phase-Transition in Cubic Spinels

It was believed that the magnetic phase transition in Mn(Co)Cr2O4 happens without assistance of any structural phase transition, which seems very exception. We discover a hitherto undetected glassy magnetic ordering of the spiral-spin components triggering the long-range transition (TN1). 

A. Das, P. Pal et al. Phys. Rev. B (Letter) 107, L100414 (2023).

5. Tuning Spin-Flop Transition to Easily Accessible 2T Field 

Multiferroic MnTiO3 (MTO) undergoes a magnetic spin-flop driven ferroelectric polarization flop beyond  6T, which we tuned to easily accessible 2T by chemistry engineering and effective reduction of effective magnetocrystalline anisotropy. 

P. Pal et al. J. Appl. Phys. 132, 183905 (2022).

4. Designing Ferroelectric Material for Enhanced Photovoltaic Effect

We carefully designed Bi−Fe codoped BaTiO3 system which provides a unique platform with the simultaneous optimization of low band gap, high ferroelectric-polarization, and reasonable conductivity, exhibiting enhanced photovoltaic response. 

P. Pal et al. The Journal of Physical Chemistry C 125, 5315 (2021).

3. Engineering Room-Temperature multiferroicity

Simultaneous presence of room-temperature ferroelectricity and ferromagnetism is not observed in any material. Here, we engineered a unique combination of  Bi doping along with Fe into BaTiO3 which provides a novel platform with effectively enhanced the magnetoelectric (ME) multiferroic response (both ferromagnetism and ferroelectricity) at room temperature..

P. Pal et al.Appl. Phys. Lett. 117, 012901 (2020). 

2. Room-Temperature Multiferroicity

Room-temperature ferroelectric and ferromagnetic material is highly demanded, however, lacks its existence. Fe-doped ferroelectric BaTiO3 showed promising results, but the discussions were confusing regarding the true origin. We investigated its true origin and show that Fe-doped BTO has a mixed-phase room-temperature multiferroicity, where the ferromagnetism comes from the majority hexagonal phase and a minority tetragonal phase gives rise to the observed weak ferroelectricity.

P. Pal et al.Phys. Rev. B 101, 064409 (2020).

1. YTiO3 -CaTiO3 Thin-Film Superlattice

YTiO3 is a ferromagnet and mott insulator in its bulk form. A designed YTiO3−CaTiO3 thin-film superlattices provides a unique platform toward emergent antiferromagnetism from epitaxially strained YTiO3 layers, which is in excellent agreement with recent theoretical predictions. 

P. Pal et al.Phys. Rev. B 98, 045420 (2018)