Integration of c-axis oriented Bi3.15Nd0.85Ti2.95Hf0.05O12/La0.67Sr0.33MnO3 ferromagnetic-ferroelectric composite film on Si substrate

Abstract

A La0.67Sr0.33MnO3 (LSMO) ferromagnetic layer and a Nd3+/Hf4+ co-substituted Bi4Ti3O12 (Bi3.15Nd0.85Ti3-xHfxO12 (BNTHx, x = 0, 0.025, 0.05, 0.1 and 0.15)) ferroelectric layer were successively deposited onto the (00 l)-oriented LaNiO3 (LNO) layer buffered (001) Si substrate via all chemical solution deposition (CSD) method. As a result, the BNTHx/LSMO ferromagnetic-ferroelectric composite films integrated on Si substrate exhibit high c-axis orientation. The Nd3+/Hf4+ co-substituted BNTHx films have the lower leakage current and the better ferroelectric properties than the mono-substituted Bi4Ti3O12 (Bi3.15Nd0.85Ti3O12 and Bi4Ti2.95Hf0.05O12) films. In particular, the BNTH0.05/LSMO/LNO film has the lowest leakage current density of 2.5 × 10−7 A/cm2 at 200 kV/cm, and the highest remnant polarization (Pr) of 27.3 μC/cm2. The BNTH0.05/LSMO/LNO composite film also exhibits the soft ferromagnetism characteristics with a high saturated magnetization of 258 emu/cm3 at 300 K, and the excellent magnetoelectric (ME) effect. The variations of ME voltage coefficient α E values with DC bias magnetic field H bias shows that the BNTH0.05/LSMO/LNO film has the high α E value at near zero H bias. Moreover, at H bias = 0 Oe, the α E value gradually increases from zero with the increasing of the AC magnetic field frequency, and eventually reaches about 18.9 V/cm·Oe at 100 kHz, suggesting the existence of self-biased ME effect.

Tunable Ferroelectricity in Ruddlesden–Popper Halide Perovskites

“…However, we observe the resistive behavior at a higher electric field likely because of the dominant ion migration over ferroelectricity, indicated by the circle-shaped P – E loop. Such a P – E loop shape has also been widely observed in various ferroelectric reports. ,, …”

“…Such a P−E loop shape has also been widely observed in various ferroelectric reports. 23,50,51 Finally, we performed MD simulations in a bid to gain deeper insights into the polarization switching behavior in these RP perovskites. Unlike the pure 2D perovskite (i.e., n ̅ = 1), which only consists of the weakly polar PEA molecule, the polarity of n ̅ = 2 to n ̅ = 5 can be enhanced by the highly polar MA + molecule (2.3 Debye).…”

“…For instance, ferroelectricity in Ruddlesden–Popper (RP) perovskite can lead to the formation of distinct electron and hole diffusion pathways toward the respective electrodes, thereby avoiding the chance encounters of opposite charges and suppressing recombination losses in solar cell devices. These diffusion pathways are mainly located at the boundaries of the ferroelectric domains inside the bulk film. − The spontaneous spatial charge separation and suppression of the recombination losses yield a higher open-circuit voltage and thus better efficiency in photovoltaics . On the other hand, such avoidance is undesirable for light-emitting diodes (LEDs) as it could lead to reduced emission efficiency as well as decreased emission color purity under sustained operations …”

Self‐biased magnetoelectric composite for energy harvesting

“…The exchange bias effect at the LSMO/LNO interface induced the horizontal shift of the hysteresis loop and the clamping effect of the LNO layer caused the LSMO film strain, which co‐contributed the SME effect. A relatively large α SME of 1.118 V cm −1 Oe −1 was observed in the BNTH/LSMO/LNO thin film at 10 kHz in a 0.5 Oe magnetic field; this finding is important in the exploration of its potential application to self‐biased transducers 106 . Li et al constructed an LSMO/BTO/LSMO epitaxial layered heterostructure on (00 l )‐oriented LaAlO 3 (LAO) single crystal substrates by PLD route.…”

“…A relatively large α SME of 1.118 V cm −1 Oe −1 was observed in the BNTH/LSMO/LNO thin film at 10 kHz in a 0.5 Oe magnetic field; this finding is important in the exploration of its potential application to self-biased transducers. 106 Li et al constructed an LSMO/BTO/LSMO epitaxial layered heterostructure on (00l)-oriented LaAlO 3 (LAO) single crystal substrates by PLD route. The compressive strain gradient induced by the exchange bias effect and lattice mismatch at the LSMO/LAO interface resulted in a H int in the ferromagnetic LSMO layer, which yielded an ME output voltage of 71 mV cm −1 Oe −1 in the absence of a bias magnetic field.…”