Journal of Physics D: Applied Physics

Fu, Yongqiang; Kong, Deqiang; Xu, Guowang; Wang, Jingze; Wu, Yaojiong; Zhang, Ruobing

doi: 10.1088/1361-6463/ad2092pmid: N/A

The issue of hair loss has become an increasing concern due to growing societal pressures. Currently available hair loss treatments often produce unsatisfactory results, cause significant physical damage, and are costly. Non-thermal atmospheric pressure plasma has been widely used in various biomedical fields, including sterilization, coagulation promotion, and cancer treatment. This paper pioneered the use of a kind of portable pulsed plasma jet power supply in the resting period of mouse hair follicle, and found that plasma jet can effectively shorten the resting period of mouse hair follicle, so that they re-enter the regeneration period and grow hair. Plasma jet provides a new treatment method for hair loss that is cheap, simple, highly effective, has no side effects and has broad application prospects.

Xie, Qijing; Huang, Huimin; Zhang, Chengliang; Zheng, Xiangyang; Shi, Haifeng

doi: 10.1088/1361-6463/ad2094pmid: N/A

The rapid recombination of photogenerated electrons and holes was an enormous hindrance constraining the photocatalytic efficiency of photocatalysis, which could be effectively solved by inducing electron spin-polarization. Herein, a series of gradient ZnFe2-xCoxO4 (ZFCO-x) magnetic compounds with spin-polarization properties were synthesized by doping Co cation into ZnFe2O4, as well as the diffraction of x-rays characterization confirmed the successful synthesis of the samples. In photodegradation experiments, ZFCO-0.8 manifested improved photocatalytic degradation efficiency in TC removal experiments with visible-light exposure and external magnetic field. Furthermore, the photodegradation experiments exhibited that the degradation efficiency of ZFCO-x could be raised through Co doping and the photocatalytic degradation efficiency was significantly improved under an external magnetic field. The sample exhibiting the most prominent enhancement was ZFCO-x with doping content of x = 0.8, which displayed 48% photocatalytic degradation performance enhancement with a magnetic field. Density functional theory was used to calculate the density of states (DOS) of materials. The calculated DOS indicated that ZFCO-0.8 exhibited the most intense spin-polarization consistent with the results of the experiment. This work is anticipated to deliver an operating method for manipulating spin-polarization in photocatalytic semiconductors to improve photocatalytic degradation efficiency.

Ballato, John; Dragic, Peter D; Digonnet, Michel J F

doi: 10.1088/1361-6463/ad1ddcpmid: N/A

It is hard to overstate the utility of lasers in modern technology. Optical-fiber-based lasers are of particular value thanks to their combination of small form factors, afforded by the coilability of the thin strands of fiber, and high beam-quality output. The optical fiber geometry also possesses a relatively high surface-area-to-volume ratio, rendering thermal management somewhat more straightforward than in other bulk laser types. Regardless, the generation of heat during the lasing process can still be problematic for a myriad of reasons, and conventional methods of thermal management do not comport with the potential compactness and elegance of fiber lasers as technological solutions. This Perspective summarizes recent advances in glass science and optical fiber engineering to support the provocative premise that heat generation in future laser systems can be entirely managed by a combination of fiber materials and novel laser physics. Letting the fiber manage heat itself would have significant impacts on enhancing system performance while greatly reducing size, weight, power-consumption, and cost.

Ateia, Ebtesam E; Elraaie, Raghda; Mohamed, Amira T

doi: 10.1088/1361-6463/ad1f31pmid: N/A

In the current study, we developed a simple and biocompatible method for producing core–shell nanoparticles (NPs). Citrate auto combustion and green procedures were used to create core–shell Ag/CoGd0.025Er0.05Fe1.925O4 (Ag/CGEFO) sample with an average crystallite size of 26.84 nm. The prepared samples were characterized via different structural techniques, such as x-ray diffraction (XRD), Raman Spectroscopy (RS), High-Resolution Transmission Electron Microscopy, and Energy Dispersive x-ray analysis. These analyses were utilized to characterize and confirm the successful formation of the core–shell architecture. For core–shell NPs, all peaks of Ag and CGEFO ferrite are detected in the XRD, confirming the co-presence of the ferrite spinel phase and the cubic Ag phase. The magnetic hysteresis curves demonstrate typical hard ferri-magnetic behavior along with maximum magnetic saturation values up to 53.74 emu g−1 for the CGEFO sample, while an enhanced coercivity is detected for the coated sample. Moreover, the width of the hysteresis loop is increased for the Ag/CGEFO sample compared to the uncoated one. This indicates that the addition of Ag as a shell increases magneto crystalline anisotropy. Moreover, the Eg of uncoated CGEFO is equal to 1.4 eV, increasing to 3.6 eV for coated ones. This implies the influence of CGEFO is diminished when the surface is coated with Ag (shell), and the reflectance of the Ag/CGEFO core–shell is nearly dependent on the reflectance of the Ag shell layer. Consequently, the Ag/CGEFO can be used as a light shielding substance.

Bairy, Raghavendra; Vijeth, H; Rajesh, K; Kulkarni, Suresh D; Gummagol, Neelamma; Murari, M S

doi: 10.1088/1361-6463/ad1eddpmid: N/A

A polycrystalline nanostructured thin film of zinc cadmium sulfide was meticulously fabricated on a glass substrate using the thermal evaporation method physical vapor deposition within a vacuum chamber. Different doping concentrations were introduced by varying the cadmium (Cd) content, resulting in Zn1-xCdxS films with Cd concentrations ranging from x = 0.00–0.20 wt %. The impact of Cd doping on the third-order nonlinear optical (TONLO) properties of these films was thoroughly studied using the Z-scan method, employing a diode-pumped solid-state continuous-wave laser. To gain insight into the structural characteristics, the Zn1-xCdxS thin films underwent analysis through x-ray diffraction. Optical studies confirmed the tunability of the optical band gap (Eg) in the Zn1-xCdxS films, ranging from 3.88 eV for undoped ZnS to 2.80 eV for the film fabricated with 20 wt. % of Cd-content. This significant reduction in ‘Eg’ renders the films highly suitable for use as absorbing layers in applications such as solar cells and optoelectronics. Surface morphology analysis, performed via field emission scanning electron microscopy, revealed noticeable alterations with increased Cd doping. Significantly, the doped films exhibited a substantial redshift in the band edge and an increase in transmittance within the visible and near-infrared regions. The investigation of TONLO properties, including the nonlinear absorption coefficient (β), nonlinear refractive index (n2) and susceptibility χ(3), yielded values ranging from 3.15 × 10−3 to 8.16 × 10−3 (cm W−1), 1.65 × 10−8 to 7.45 x 10–8 (cm2 W−1), and 3.12 × 10−5 to 7.86 × 10−5 (esu), respectively. These results indicate the presence of self-defocusing nonlinearity in the films. Overall, the outcomes underscore the potential of Cd-doped ZnS nanostructures in modifying surface morphology and enhancing NLO characteristics. Zn1-xCdxS thin films exhibit promise for applications in nonlinear optical devices, as evidenced by these encouraging findings.

Wang, Zidong; Xu, Hua; Shen, Xiangyan; Liu, Yan

doi: 10.1088/1361-6463/ad2093pmid: N/A

Exploration and manipulation of terahertz signal generators are crucial steps in the creation of numerous applications. Antiferromagnets can boost output signal frequency to the terahertz range. We propose a nanometer-scale generating device that produces terahertz signals by DC-exciting in a bilayer structure. The structure comprises a heavy metal layer (Pt) and a non-collinear antiferromagnetic layer (NiF2), where the magnetic moments in NiF2 with single-ion anisotropy are excited by the spin current from the Pt layer through spin–orbit torque. The inhomogeneous dynamic behaviors of the magnetic moments of NiF2 are calculated by the Landau–Lifshitz–Gilbert equation. It is found that terahertz-frequency AC can be reliably output from the bilayer structure, with the frequency that can reach to 1.82 terahertz. The oscillator shows the best performance when the polarized direction of the spin current is along the hard-axis of NiF2. The frequency and the amplitude of the AC can be adjusted by the current density, thickness and damping constant of the NiF2 layer. The threshold currents for exciting and maintaining the stable oscillation increase with the thickness and damping constant of the NiF2.

Shi, Ruyue; Chen, Hailiang; Li, Hongwei; Liu, Chaoyi; Li, Lida; Yang, Sigang

doi: 10.1088/1361-6463/ad18f9pmid: N/A

In this paper, Vernier effect was experimentally excited through paralleling Sagnac interferometer (SI) and Mach–Zehnder interferometer (MZI). SI was fabricated using a 38 cm long panda-shaped polarization maintaining fiber in the Sagnac loop, while MZI was made through tapering a single mode fiber. Experimental results showed that the measurement sensitivities of strain and temperature based on the paralleled SI and MZI were 51.97 pm µϵ−1 and 2.94 nm °C−1 respectively, which were enhanced by about three times than based on an individual SI whose measurement sensitivities of strain and temperature were 18.24 pm µϵ−1 and 0.98 nm °C−1 correspondingly. Theoretical analysis of the single interference and paralleled interferences were verified by the experimental results. The proposed sensor shows the advantages of simple in fabrication, high sensitivity, and good hysteresis, is a strong competitor in monitoring the strain and temperature.

Li, Jing; Gao, Yu; Liu, Baixin; Guo, Chenyi; Gao, Junguo; Chen, Yu; Du, Boxue

doi: 10.1088/1361-6463/ad1ebdpmid: N/A

This paper reports on thermal and electrical conduction properties of polypropylene (PP)-based nanocomposite used for high voltage direct current cable insulation. To improve the thermal conductivity of the PP/propylene-based elastomer (PBE) blend (noted as PB), boron nitride (BN) nanosheets with high thermal conductivity are added. The pretreatment process through template method is to obtain a three-dimensional (3D) network structure composed of BN nanosheets (noted as 3DBN). Then the 3DBN is added into the PP/ PBE blend, in which the 3D networks are locally arranged and the other BN nanosheets are randomly dispersed. Thermal conductivity is estimated, while electrical conductivity is measured under electric fields of 5–40 kV mm−1 at various temperatures. Carrier trap distribution is derived from isothermal surface potential decay method. In addition, the microstructure and crystallization characteristics of the nanocomposites are measured. The results show that the thermal conductivity of the PP/PBE blend is improved obviously by the addition of the locally arranged 3DBN, and that of PB-3DBN-10 is increased by 16% compared with that of PB. Deep traps are introduced by the dispersed BN nanosheets and the electrical conduction is reduced, which becomes increasingly evident with the filler content and temperature. It is suggested that the introduction of thermal conductive fillers with a 3D network structure and well-dispersed state can synergistically enhance the thermal conductivity and insulation performances of the PP-based material.

Yao, Liqiang; Ji, Ruoyun; Wu, Songsong; Jiao, Jinlong; He, Fuxiu; Wang, Dan; Wang, Jianyuan; Li, Cheng; Huang, Wei; Ke, Shaoying; Lin, Guangyang; Chen, Songyan

doi: 10.1088/1361-6463/ad1f32

Guo, Fei; Xie, Yuanmiao; Huang, Xiaoqi; Li, Feng; Liu, Baosheng; Dong, Xinwei; Zhou, Jin

doi: 10.1088/1361-6463/ad1cbfpmid: N/A

This study proposes a novel approach to enhanced the perpendicular magnetic anisotropy (PMA) of Fe adsorbed on a MoSi2N4 substrate through hole doping. First principles calculations are employed to investigate the PMA of freestanding Fe and Fe/MoSi2N4 complex system. It is found that the PMA of Fe atom slightly increases from freestanding Fe monolayer to the Fe/MoSi2N4 system, which is attributed to the overlap between Fe-3d and N-2p orbitals. More interestingly, it is found that the PMA of Fe atoms in Fe/MoSi2N4 can be further enhanced by hole doping, which enables the PMA to increase significantly, up to four times the original value. This finding provides a promising way to enhance the PMA in two-dimensional (2D) spintronic devices. These results offering potential applications in developing advanced 2D spintronic devices.