Tailoring Dzyaloshinskii-Moriya Interaction and Spin-Hall Topological Hall Effect in Insulating Magnetic Oxides by Interface Engineering.

Chiral spin textures, as exotic phases in magnetic materials, hold immense promise for revolutionizing logic, and memory applications. Recently, chiral spin textures have been observed in centrosymmetric magnetic insulators (FMI), due to an interfacial Dzyaloshinskii-Moriya interaction (iDMI). However, the source and origin of this iDMI remain enigmatic in magnetic insulator systems. Here, the source and origin of the iDMI in Pt/Y3Fe5O12 (YIG)/substrate structures are deeply delved by examining the spin-Hall topological Hall effect (SH-THE), an indication of chiral spin textures formed due to an iDMI. Through carefully modifying the interfacial chemical composition of Pt/YIG/substrate with a nonmagnetic Al3+ doping, the obvious dependence of SH-THE on the interfacial chemical composition for both the heavy metal (HM)/FMI and FMI/substrate interfaces is observed. The results reveal that both interfaces contribute to the strength of the iDMI, and the iDMI arises due to strong spin-orbit coupling and inversion symmetry breaking at both interfaces in HM/FMI/substrate. Importantly, it is shown that nonmagnetic substitution and interface engineering can significantly tune the SH-THE and iDMI in ferrimagnetic iron garnets. The approach offers a viable route to tailor the iDMI and associated chiral spin textures in low-damping insulating magnetic oxides, thus advancing the field of spintronics.

Partial substitution of wheat flour with soybean and gluten powder: impact on flavor characteristics of Pixian Douban-Meju and its quality.

BACKGROUND: In this study, different proportions of soybean flour and gluten flour were used as partial replacements for wheat flour for the fermentation of Pixian Douban-Meju (PXDB). The aim was to study the effects of soybean flour/gluten flour on the quality improvement of PXDB. RESULTS: In comparison with the control group (CT) (0% substitution of wheat flour), substitution of wheat flower with 12.5% soybean flour (the H2 group), 7.5% gluten flour (G2), and 10% gluten flour (G3) improved the amino acid nitrogen content by 3.8%, 5.6%, and 9.4% respectively. The mixtures of wheat flour and gluten flour (G2 or G3) increased the organic acid and free amino acid content. The results of two-dimensional gas chromatography mass spectrometry (GC × GC-MS) showed that the amount of key aroma substances increased about sixfold in comparison with the CT group (194.61 g.kg-1 ), achieving 1283.67, 1113.883, and 1160.19 g.kg-1 in the H2, G2, and G3 groups, respectively. There were also more aldehydes and pyrazines in all the substitution groups. Quantitative descriptive analysis indicated that the G3 sample presented the best organoleptic quality with a reddish-brown color and a more mellow aroma than the control sample. CONCLUSION: In conclusion, the fermentation of G3 resulted in higher quality PXDB-meju, showing that partial substitution of wheat flour with gluten improved the quality of PXDB. © 2023 Society of Chemical Industry.

Anomalous polarization enhancement in a van der Waals ferroelectric material under pressure.

CuInP2S6 with robust room-temperature ferroelectricity has recently attracted much attention due to the spatial instability of its Cu cations and the van der Waals (vdW) layered structure. Herein, we report a significant enhancement of its remanent polarization by more than 50% from 4.06 to 6.36 µC cm-2 under a small pressure between 0.26 to 1.40 GPa. Comprehensive analysis suggests that even though the hydrostatic pressure suppresses the crystal distortion, it initially forces Cu cations to largely occupy the interlayer sites, causing the spontaneous polarization to increase. Under intermediate pressure, the condensation of Cu cations to the ground state and the polarization increase due cell volume reduction compensate each other, resulting in a constant polarization. Under high pressure, the migration of Cu cations to the center of the S octahedron dominates the polarization decrease. These findings improve our understanding of this fascinating vdW ferroelectric material, and suggest new ways to improve its properties.

Providing or receiving alloparental care promote partner preference and alter central oxytocin and dopamine systems in adult mandarin voles.

Juveniles of cooperative breeding species usually remain in the natal area and provide care to younger siblings, a behavior considered one form of alloparenting in the natural condition. Previous studies have demonstrated the effects of providing or receiving alloparental care on adult behaviors, including anxiety-like behavior, social interaction, and parental behavior, but little is known about the influences on species-typical bonding behaviors, such as pair-bond formation. In this study, we explored this concept using socially monogamous mandarin voles (Lasiopodomys mandarinus). As the oxytocin (OT) and dopamine systems are involved in alloparental and pair-bonding behaviors, we also examined the levels of central OT and tyrosine hydroxylase (TH), as well as OT receptor (OTR) and dopamine D1-type and D2-type receptors (D1R and D2R) mRNA expression in the nucleus accumbens (NAcc) and amygdala to investigate the underlying mechanisms. Our results show that mandarin voles providing alloparental care to younger siblings displayed facilitation of partner preference formation, lower levels of OT expression in the paraventricular nucleus of the hypothalamus (PVN) and lateral hypothalamus (LH), and increased OTR and D2R mRNA expression in the NAcc compared to controls. Individuals receiving alloparental care also demonstrated facilitation of partner preference formation in adult voles. Additionally, alloparental care enhanced OT expression in the PVN, anterior medial preoptic nucleus (MPOAa), medial amygdala (MeA), and TH expression in the ventral tegmental area (VTA) and zona incerta (ZI). Furthermore, males displayed decreased D1R mRNA expression in the NAcc, whereas females showed slightly increased D2R expression in the amygdala. These results demonstrate that providing or received alloparental care can promote partner preference formation in monogamous species and that these changes are associated with altered OT and dopamine levels and their receptors in specific brain regions.

Adolescence Predatory Risk Alters Social Behaviors and Cognitive Ability and Central Oxytocin and Vasopressin Expression in Adult Brandt's Voles.

INTRODUCTION: Stress during adolescence causes long-term behavioral changes in adulthood. We previously found that adolescent exposure to predatory risk augments adolescent social contact and adult parental behavior in Brandt's voles (Lasiopodomys brandtii). METHODS: Here, we determined whether this experience alters sexual behavior, pair-bond formation, and recognition ability as well as basal HPA axis activity, central oxytocin (OT), and arginine-vasopressin (AVP) expression in adulthood. RESULTS: In the social interaction test, repeated cat odor (CO) exposure enhanced the frequency of lordosis by female voles toward an unfamiliar opposite-sex conspecific. CO voles preferred to engage with their partners after 48-h cohabitation whereas the control groups did not, which may reflect stable pair bonds in the CO treatment group. Furthermore, adolescent exposure to CO inhibited novel object recognition and place recognition ability, while it influenced social recognition only among adult males. No effect of adolescent CO exposure was observed for basal HPA axis activity, showing a habituation effect. Finally, we found that CO exposure increased OT and decreased AVP expression in the hypothalamus, including the paraventricular nucleus and anterior hypothalamus. The levels of OT in the medial amygdala were lower, and AVP in the lateral septum was higher in CO voles compared with the control. CONCLUSION: These findings demonstrate that adolescent exposure to predator risk promotes adult reproductive behavior of Brandt's voles. Deficits in recognition ability may necessitate alterations in reproductive strategies to enhance inclusive fitness. OT and AVP systems may play a modulatory role in the alteration of social behaviors elicited by adolescent predatory risk.

Strain-Tunable Interfacial Dzyaloshinskii-Moriya Interaction and Spin-Hall Topological Hall Effect in Pt/Tm3Fe5O12 Heterostructures.

The interfacial Dzyaloshinskii-Moriya interaction (DMI) in heavy-metal/ferromagnet heterostructures enables to stabilize and manipulate novel topological spin textures, such as skyrmions, which arise as potential logic and memory devices for future information technology. Along these lines, we study in this work the topological spin textures in the films of magnetic insulators by detecting the spin-Hall topological Hall effect (SH-THE). The SH-THE presents obvious dependence of epitaxial strain in Pt/Tm3Fe5O12 (TmIG) bilayers deposited on a series of (111)-oriented garnet substrates, indicating that the topological spin textures can be tuned by epitaxial strain in this system. It is interesting to note that the room-temperature and low-field peak of SH-THE is also recorded within the Pt/TmIG bilayer configuration. We have also examined the interfacial DMI in the Pt/TmIG bilayers by an extended droplet model. The results indicate that the epitaxial strain can effectively change the interfacial DMI in this system, suggesting that the strain-induced modification of the interfacial DMI is the driving force for the SH-THE and topological spin textures in the Pt/TmIG bilayers. Our outcomes open new exciting avenues and opportunities in engineering chiral magnetism and examining the future skyrmion technology in magnetic insulators through the application of epitaxial strain.

Perpendicular Manganite Magnetic Tunnel Junctions Induced by Interfacial Coupling.

The half-metallic manganite oxide La2/3Sr1/3MnO3 (LSMO) has a very high spin polarization of ∼100%, making it ideal for ferromagnetic electrodes to realize tunneling magnetoresistance (TMR). Because of the in-plane magnetic anisotropy of the ferromagnetic LSMO electrode, which leads to the density limit of memory, realizing perpendicular tunneling in manganite-based magnetic tunnel junctions (MTJ) is critical for future applications. Here, we design and fabricate manganite-based MTJs composed of alternately stacked cobaltite and manganite layers that demonstrate strong perpendicular magnetic anisotropy (PMA) induced by interfacial coupling. Moreover, spin-dependent tunneling behaviors with an out-of-plane magnetic field were observed in the perpendicular MTJs. We found that the direct tunneling effect plays a dominant role in the low bias region during the transport behavior of devices, which is associated with thermionic emission of electrons or oxygen vacancies in the high bias region. Our works of realizing perpendicular tunneling in manganite-based MTJs lead to new approaches for designing and developing all-oxide spintronic devices.

Super-Flexible Freestanding BiMnO3 Membranes with Stable Ferroelectricity and Ferromagnetism.

Multiferroic materials with flexibility are expected to make great contributions to flexible electronic applications, such as sensors, memories, and wearable devices. In this work, super-flexible freestanding BiMnO3 membranes with simultaneous ferroelectricity and ferromagnetism are synthesized using water-soluble Sr3 Al2 O6 as the sacrificial buffer layer. The super-flexibility of BiMnO3 membranes is demonstrated by undergoing an ≈180° folding during an in situ bending test, which is consistent with the results of first-principles calculations. The piezoelectric signal under a bending radius of ≈500 µm confirms the stable existence of electric polarization in freestanding BiMnO3 membranes. Moreover, the stable ferromagnetism of freestanding BiMnO3 membranes is demonstrated after 100 times bending cycles with a bending radius of ≈2 mm. 5.1% uniaxial tensile strain is achieved in freestanding BiMnO3 membranes, and the piezoresponse force microscopy (PFM) phase retention behaviors confirm that the ferroelectricity of membranes can survive stably up to the strain of 1.7%. These super-flexible membranes with stable ferroelectricity and ferromagnetism pave ways to the realizations of multifunctional flexible electronics.

Ferroelectricity and Ferromagnetism Achieved via Adjusting Dimensionality in BiFeO3/BiMnO3 Superlattices.

Integrating characteristics of materials through constructing artificial superlattices (SLs) has raised extensive attention in multifunctional materials. Here, we report the synthesis of BiFeO3/BiMnO3 SLs with considerable ferroelectric polarizations and tunable magnetic moments. The polarization of BiFeO3/BiMnO3 SLs presents a decent value of 12 µC/cm2, even as the dimensionality of BiFeO3 layers per period is reduced to about five-unit cells when keeping the BiMnO3 layers same. Moreover, it is found that the tunable magnetic moments of SLs are linked intimately to the dimensionality of BiFeO3 layers. Our simulations demonstrate that the superexchange interaction of Fe-O-Mn tends to be antiferromagnetic (AFM) with a lower magnetic domain formation energy rather than ferromagnetic (FM). Therefore, as the dimensionality of BiFeO3 per period is reduced, the AFM superexchange interaction between BiFeO3 and BiMnO3 in the SLs becomes weak, promoting a robust magnetization. This interlayer modulation effect in SLs presents an alluring way to accurately control the multiple order parameters in a multiferroic oxide system.

Tuning ferroelectricity and ferromagnetism in BiFeO3/BiMnO3 superlattices.

Multiferroic materials with multifunctional characteristics play a critical role in the field of microelectronics. In a perovskite oxide, ferroelectric polarization and ferromagnetism usually cannot coexist in a single-phase material at the same time. In this work, we design a superlattice structure composed of alternating BiFeO3 and BiMnO3 layers and illustrate how tuning the supercell size of epitaxial BiFeO3/BiMnO3 superlattices facilitates ferroelectric polarization while maintaining relatively strong ferromagnetism. A comprehensive investigation reveals that the enhanced ferroelectric polarization of BiMnO3 layers originates from the induction effect induced by a strong polarization field generated by the adjacent ferroelectric BiFeO3 layers. For the magnetic behavior, we consider the existence of interfacial antiferromagnetic superexchange interaction of Fe-O-Mn between BiFeO3 and BiMnO3 layers in our superlattices. This modulation effect of artificial superlattices provides a platform to accurately control the multiple order parameters in a multiferroic oxide system.

Large-scale multiferroic complex oxide epitaxy with magnetically switched polarization enabled by solution processing.

Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi(1-y)/2Fe y Mg(1-y)/2O3-(x)CaTiO3 (BTFM-CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 µB/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7-3.0 × 10-7 s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM-CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications.

RhoG/Rac1 signaling pathway involved in migration and invasion of salivary adenoid cystic carcinoma cells.

OBJECTIVES: This study aimed to explore whether RhoG/Rac1 was involved in migration and invasion of salivary adenoid cystic carcinoma (SACC). MATERIALS AND METHODS: RhoG and Rac1 were evaluated in two SACC cell lines, namely SACC-83 and SACC-LM, with low and high rates of lung metastasis, respectively. Functional changes were evaluated using cell proliferation, transwell, and wound-healing assays, and molecular events were investigated using real-time PCR and Western blot assays. RESULTS: RhoG and Rac1 were highly expressed and more activated in SACC-LM cells than in SACC-83 cells. RhoG overexpression promoted SACC-83 cell migration and invasion through activating Rac1. The knockdown of RhoG or Rac1 partially blocked epiregulin-induced migration and invasion in SACC-83 cells. Epiregulin-induced activation of RhoG/Rac1 in SACC-83 cells was blocked by a Src inhibitor, or an AKT inhibitor or AKT siRNA, or an ERK1/2 inhibitor. Moreover, the epiregulin-induced phosphorylation of AKT and ERK1/2 in SACC-83 cells was blocked by a Src inhibitor, and the epiregulin-induced phosphorylation of ERK1/2 was blocked by an AKT inhibitor or AKT siRNA. Overexpression of activated AKT induced activation of ERK1/2 and RhoG. CONCLUSIONS: RhoG/Rac1 signaling pathway was involved in SACC cell migration and invasion. RhoG/Rac1 at least partially mediated epiregulin/Src/AKT/ERK1/2 signaling to promote SACC cell migration and invasion.

Strain-Enhanced Charge Transfer and Magnetism at a Manganite/Nickelate Interface.

The strain effect on charge transfer in correlated oxide La0.8Sr0.2MnO3/NdNiO3 (LSMO/NNO) heterostructures is investigated. This is achieved by carefully tailoring the strain on the two layers using various substrates. In contrast to bare LSMO films, the strain dependence of the enhanced magnetic moment of the LSMO/NNO bilayers strongly suggests that the charge transfer can be controlled via strain engineering in complex oxide heterostructures. Furthermore, our study also reveals that the coercive field, exchange bias, and conductivity are dramatically affected by the strain-modulated charge transfer in LSMO/NNO heterostructures. Our work thus points out a new path to control electronic states in oxide heterostructures to advance the use of interfaces in oxide-based electronics.

Low-energy Resistive Random Access Memory Devices with No Need for a Compliance Current.

A novel resistive random access memory device is designed with SrTiO3/ La2/3Sr1/3MnO3 (LSMO)/MgAl2O4 (MAO)/Cu structure, in which metallic epitaxial LSMO is employed as the bottom electrode rather than traditional metal materials. In this device, the critical external compliance current is no longer necessary due to the high self-resistance of LSMO. The LMSO bottom electrode can act as a series resistor to offer a compliance current during the set process. Besides, the device also has excellent switching features which are originated in the formation of Cu filaments under external voltage. Therefore it provides the possibility of reducing power consumption and accelerating the commercialization of resistive switching devices.

Co nanoparticles induced resistive switching and magnetism for the electrochemically deposited polypyrrole composite films.

The resistive switching behavior of Co-nanoparticle-dispersed polypyrrole (PPy) composite films is studied. A novel design method for resistive random access memory (ReRAM) is proposed. The conducting polymer films with metal nanocrystal (NC)-dispersed carbon chains induce the spontaneous oxidization of the conducting polymer at the surface. The resistive switching behavior is achieved by an electric field controlling the oxygen ion mobility between the metal electrode and the conducting polymer film to realize the mutual transition between intrinsic conduction (low resistive state) and oxidized layer conduction (high resistive state). Furthermore, the formation process of intrinsic conductive paths can be effectively controlled in the conducting polymer ReRAM using metal NCs in films because the inner metal NCs induce electric field lines converging around them and the intensity of the electric field at the tip of NCs can greatly exceed that of the other region. Metal NCs can also bring new characteristics for ReRAM, such as magnetism by dispersing magnetic metal NCs in polymer, to obtain multifunctional electronic devices or meet some special purpose in future applications. Our works will enrich the application fields of the electromagnetic PPy composite films and present a novel material for ReRAM devices.