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Qingtian paddy field carp (PF-carp) is a local carp cultivated in the paddy field of Qingtian, Zhejiang. This rice-fish co-culture system has been recognized as one of the Globally Important Agriculture Heritage Systems (GIAHS). PF-carp has been acclimatized to the high-temperature environment of shallow paddy fields after several centuries of domestication. To reveal the physiological and molecular regulatory mechanisms of PF-carp, we chose to use 28°C as the control group and 34°C as the treatment group. We measured biochemical parameters in their serum and hepatopancreases and also performed transcriptome sequencing analysis. Compared with the control group, the serum levels of malondialdehyde (MDA), glucose (GLU), glutathione peroxidase (GSH-Px), catalase (CAT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) show no significant change. In addition, superoxide dismutase (SOD), GSH-Px, and CAT also show no significant change in hepatopancreases. We identified 1,253 differentially expressed genes (DEGs), and their pathway analysis revealed that heat stress affected AMPK signaling pathway, protein export, and other biological processes. It is worth noting that protein processing in the endoplasmic reticulum (ER) was the most significantly enriched pathway identified by the Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analysis (GSEA). Significantly higher levels of HSP40, HSP70, HSP90, and other ubiquitin ligase-related genes were upregulated. In summary, heat stress did not lead to tissue damage, inflammation, oxidative stress, and ER stress in the hepatopancreases of PF-carp. This study provides valuable insights into the adaptation mechanism of this species to the hightemperature environment of paddy fields. [ABSTRACT FROM AUTHOR]

In this work, the hysteresis loops of ultra thin CoFeB films with perpendicular anisotropy are simulated using a micromagnetic model with microstructure included. An inhomogeneous region of the perpendicular uniaxial anisotropy constant K is introduced in the model, and this is the key factor to explain why the in-plane saturation field is several thousand Oersted, while the perpendicular coercivity can be on the order of 100 Oersted. Tendency of the simulated loops with increasing total simulation size reveals that this model is reliable, and the calculated loops basically agree with experiments. The effects of different K distribution, defect sizes, defect patterns, and higher order magnetic anisotropy on simulated M-H loops are also discussed in the paper. [ABSTRACT FROM AUTHOR]

The magnetostatic interactions among CoFeB layers with perpendicular anisotropy are studied in [Ta/CoFeB/MgO]N multilayers by measured loops, magnetic domains, and a simple model. With increasing repeat number N or decreasing separation thickness d between adjacent CoFeB layers, higher magnetostatic interaction among CoFeB layers results in bow-tie shape perpendicular loops and shrinking of domain size at remanence state. The measured nucleation field Hn of bow-tie shape perpendicular loops can be explained by a simple theoretical model including the intralayer and interlayer magnetostatic interactions among CoFeB layers with a certain domain size. [ABSTRACT FROM AUTHOR]

We report an orientation-controlled FePt thin films grown nonexpitaxially on oxidized Si substrates without using any underlayers. After 700 °C annealing, the FePt single layer with thickness less than 10 nm shows good (001) texture and perpendicular anisotropy. The scanning electron microscope images indicate that these films are composed of isolated islands. For the films thicker than 20 nm, the films become continuous and (111) orientation appears. The transition of film texture relates to the change of morphology of the films. Finally, a theoretical mode based on minimizing surface energy is proposed to explain the texture variation in the films. [ABSTRACT FROM AUTHOR]

L10 ordered FePt thin films with face-centered-tetragonal (001) texture have been prepared by magnetron sputtering on Cr100-xWx underlayer. The dependence of Cr100-xWx microstructure and FePt texture on the W content in the Cr underlayer was investigated. The addition of W element in Cr underlayer enhances the Cr (200) texture and increases the lattice constant of Cr, which is favorable for lowering the transformation temperature from fcc to fct phase because of the increase of the tensile stress along the FePt a axis. A good FePt (001) texture is obtained on the Cr85W15 underlayer with a substrate temperature of 400 °C. The coercivity of FePt thin films on CrW underlayer is higher than on Cr underlayer and increases with increasing W content in the Cr underlayer because the formation of the CrW alloy inhibits the diffusion between FePt and CrW layer. A 5 nm Pt intermediate layer was employed to suppress the diffusion between FePt and CrW underlayer further. [ABSTRACT FROM AUTHOR]

Spin-orbit torques (SOTs) in Ta/CoFeB/MgO structures are studied by harmonic voltage method. The results indicate that both Slonczewski-like (HSL) and field-like (HFL) effective field are enhanced by annealing in the film stacks with various Ta thicknesses. Investigation of the crystallographic phase of the Ta layers and resistance of Hall bar devices suggest that annealing may induce a phase transformation in the Ta layers from the α to the β phase, which results in the enhanced HSL of the annealed samples. Current-induced magnetization switching experiments revealed a corresponding decrease of the switching current in the annealed samples because of their enhanced SOTs. [ABSTRACT FROM AUTHOR]

The anomalous Hall effect (AHE) was used to investigate the magnetization dynamics of an ultrathin (1.3nm) CoFeB magnetic multilayer with perpendicular magnetic anisotropy (PMA). By directly sending a radio frequency (rf) current into a millimeter-sized film sample without any lithography process, a resonant dc voltage can be detected along the Hall direction. This method was used to study the dynamic properties of ultrathin CoFeB films, such as the gyromagnetic ratio, amplitude of PMA field, and magnetic damping. The dc voltage was proven to be the consequence of spin rectification enabled by the AHE, and the dynamic magnetization was driven by the Oersted field and spin current from the electric current in the adjacent Ta layer. [ABSTRACT FROM AUTHOR]

Spin-orbit torque (SOT)-induced magnetization switching under small in-plane magnetic fields in as-deposited and annealed Ta/CoFeB/MgO structures is studied. For the as-deposited samples, partial SOT-induced switching behavior is observed under an in-plane field of less than 100 Oe. Conversely, for the annealed samples, an in-plane field of 10Oe is large enough to achieve full deterministic magnetization switching. The Dzyaloshinskii-Moriya interaction at the Ta/CoFeB interface is believed to be the main reason for the discrepancy of the requisite in-plane magnetic fields for switching in the as-deposited and annealed samples. In addition, asymmetric field dependence behavior of SOT-induced magnetization switching is observed in the annealed samples. Deterministic magnetization switching in the absence of an external magnetic field is obtained in the annealed samples, which is extremely important to develop SOT-based magnetoresistive random access memory. [ABSTRACT FROM AUTHOR]

Films with a structure of Ta (5 nm)/Co20Fe60B20 (0.8-1.5 nm)/MgO (1 nm)/Ta (1 nm) were deposited on Corning glass substrates by magnetron sputtering. The as-deposited films with CoFeB layer thickness from 0.8 to 1.3 nm show perpendicular magnetic anisotropy (PMA). After annealing at a proper temperature, the PMA of the films can be enhanced remarkably. A maximum effective anisotropy field of up to 9 kOe was obtained for 1.0- and 1.1-nm-thick CoFeB layers annealed at an optimum temperature of 300 °C. A 4-kOe magnetic field was applied during annealing to study its effect on the PMA of the CoFeB layers. The results confirmed that applying a perpendicular magnetic field during annealing did not improve the maximum PMA of the films, but it did enhance the PMA of the thinner films at a lower annealing temperature. [ABSTRACT FROM AUTHOR]

Laser induced magnetization dynamic behaviors of SmxFe1–x thin films with tunable x (0.25 ≤ x ≤ 0.5) are investigated by the time-resolved magneto-optical Kerr effect. It is found that the demagnetization process is accomplished by a two-stage process, the demagnetization time of stage I is within 1.0 ps (t1) for all the samples with different x, while it increases from 0 to 16 ps at stage II (t2) due to the reduced exchange coupling. By introducing an additional magneto-elastic energy contribution, the dispersion relation of precession frequency is deduced, by which the field-dependent frequency curves are well fitted. [ABSTRACT FROM AUTHOR]

Interfacial Dzyaloshinskii–Moriya interaction (iDMI) receives a lot of attention due to its potential for spintronics devices. The physical understanding of the artificial approaches that control the strength of iDMI remains complicated. In the Ta/Pt/CoFeB/MgO/Ta system, the strength of the iDMI D and the efficiency of the damping-like spin Hall torque (DL-SHT) have been quantified utilizing Brillouin light scattering, spin-torque ferromagnetic resonance, and spin Hall magnetoresistance. A linear relationship between D and DL-SHT efficiency was obtained, indicating that DL-SHT efficiency governed by itinerant electron spin is a comprehensive parameter for iDMI study. [ABSTRACT FROM AUTHOR]

The double-shifted magnetic hysteresis loops, which are accompanied by the formation of bi-domain state, are normally observed after zero field cooling a demagnetized sample or as-deposited ferromagnetic (FM)/antiferromagnetic (AFM) structures. In the pioneer works, this phenomenon was explained by the imprinting of ferromagnetic FM domain in AFM layer, however the interaction between the FM and AFM domain has never been discussed. In this work, we observed double-shifted magnetic hysteresis loops and bi-domain state in [Co 0.3/Ni 0.4i]N/IrMn multilayers with perpendicualr magnetic anisotropy. By comparing the domain patterns in (Co 0.3/Ni 0.4)N/IrMn multilayers, we may conclude that the bi-domain state in FM/AFM structure is related to both the FM and AFM domain, and the domain size is determined by the minimum of the total energy in the FM/AFM system through the interficial coupling. [ABSTRACT FROM AUTHOR]

Magnetic bubbles are topological spin textures that offer interesting physics and great promise for next-generation information storage technologies. The main obstacles so far are that magnetic bubbles are generated with no field stimuli in new material systems at room temperature. Here, we report the observation of individual magnetic bubbles and its high-frequency measurement at room temperature in an exchange-coupled [Co/Pd]4/Py multilayers. We demonstrate that the emergence of magnetic bubbles at remanence can be tuned by the in-plane tilted magnetic field (roughly 3°) along the film plane at room temperature. High frequency results indicate that the presence of magnetic bubbles leads to broadening of the magnetic permeability spectrum lines (due to the non-uniformity of the magnetic moments). Our findings may help to facilitate the application of bubble-based devices at room temperature in exchange-coupled magnetic multilayers. [ABSTRACT FROM AUTHOR]

The stabilization of skyrmion bubbles in [Ta(tTa)/CoFeB(1.1 nm)/MgO(1.0 nm)]15/Ta(2.0 nm) magnetic multilayers with perpendicular magnetic anisotropy is investigated. The size of the skyrmion bubbles can be controlled by tuning the Ta interlayer thickness. Because the perpendicular anisotropy constant is large in samples with a thin Ta interlayer, we can observe nanoscale skyrmion bubbles in our system. This finding provides a means to control the skyrmion size without using an external magnetic field. Moreover, we found that skyrmion bubbles can be created by a magnetic tip and subsequently be deleted. Our novel findings provide insight into skyrmion-based spintronic devices. [ABSTRACT FROM AUTHOR]

Co/Ni multilayers with different layer thicknesses and repetition numbers were fabricated by magnetron sputtering. The films with appropriate Co and Ni layer thicknesses show strong perpendicular magnetic anisotropy. The results of magnetic force microscopy indicate that the films show a maze domain in the demagnetization state and that the domain width decreases with increasing layer thickness and repetition number. The magnetostatic and domain wall energies of the film stack were calculated on the basis of an irregular maze domain pattern. The results suggest that the magnetostatic energy is the main reason for the variation of the domain width in Co/Ni multilayers. [ABSTRACT FROM AUTHOR]

The effect of electric field (E-field) on the magnetism of FePt thin films in FePt/0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) heterostructures was investigated by anomalous Hall effect measurement. For FePt films of different thicknesses, the coercivity vs E-field curves show a typical butterfly-like loop behavior. Further results indicate that the coercivity variation is composed of the volatile symmetrical butterfly-like loop and nonvolatile hysteresis loop-like parts, which originate from the volatile and nonvolatile strains induced by the E-field in the PMN–PT(001) substrate, respectively. No significant difference has been observed after inserting a 2 nm W interlayer, suggesting that the charge-mediated coercivity variation is negligible in FePt/PMN–PT heterostructures. [ABSTRACT FROM AUTHOR]