Fig. 5: Polarization-induced ferromagnetism at the ferroelectric/insulator interface.
From: Emergent properties at oxide interfaces controlled by ferroelectric polarization
a–d The conductance of SP-2DEG at STO/PZT interface. a HAADF-STEM image and (b) corresponding EELS spectra in STO/PZT(/DSO) heterostructure. The broadened peaks in STO near the interface are attributed to the presence of Ti3+ near the STO/PZT interface. c Representative Andreev spectra (open circles) of point contact between Pb superconductor and STO/PZT interface with the best fits to the modified Blonder–Tinkham–Klapwijk (BTK) model (solid curves), where T = 1.51 K, P = 0.50, Δ = 1.31 meV, rE = 3.76, Z = 0.21, and R = 899 Ω. The inset is the schematic of point contact established at the STO/PZT interface. d 1000 Oe cool-down for three (5, 10, 20 nm) STO/50 nm PZT/DSO sample and its Kerr signal image mapping at 4 K under 1000 Oe field, showing uniform ferromagnetism signal distribution. Scale bar, 15 μm. Reproduced with permission from ref. 80. Copyright [2018] {Springer Nature}. e–g Ferromagnetism of STO/PTO heterointerface. e HAADF-STEM image of STO/PTO interface. The EMCD was taken in the marked areas (f). The EMCD patterns of STO/PTO heterointerface. g M−H curves of STO/PTO heterostructures at different temperatures. Reproduced with permission from ref. 104. Copyright [2020] {Elsevier}.
