JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 16
·13469-13476
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IF 2.22
Wang Li,Yang Chaoqun,Jin Hongjun,Hu Yue,Li Ji,Xu Shichong,Li Haibo
CoFe 2 O 4 /CoFe 2 nanocomposites with exchange coupling behavior have been obtained from a two-step process. First, CoFe 2 O 4 nanoparticles with size of 11 nm were synthesized using a co-precipitation method. And second, the as-synthesized CoFe 2 O 4 nanoparticles were reduced under mixed gas (Ar 95% + H 2 5%) for 1 h at different temperatures. The structure, phase, particle size, morphology, and magnetic properties with the reduction temperature were studied. X-ray diffraction and Mössbauer spectroscopy results show the whole process from pure CoFe 2 O 4 hard magnetic phase to pure CoFe 2 soft magnetic phase when the reduction temperature increases from 400 to 700 °C, and CoFe 2 O 4 /CoFe 2 hard/soft nanocomposites are obtained at 500 and 600 °C. Magnetic measurement result show there is a stronger exchange coupling interaction between CoFe 2 O 4 and CoFe 2 for the sample reduced at 500 °C, but not in the sample reduced at 600 °C. A giant 76% enhancement of the maximum magnetic energy product (BH) max compared with pure CoFe 2 O 4 will be of technological significance in the future.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Jianfeng Dai,Xinchao Wen,Wei Feng,Chen Cheng,Danqiang Huang
Nanocomposite SrFe 12 O 19 @ZnFe 2 O 4 with core-shell structure has been synthesized in one step via coaxial electrospinning followed by heat treatment in air. The samples comprise two phases, the structure change from fiber coated particles to core-shell fibers, and finally form a scattered sheet structure. The inner diameter of the nanofiber with core-shell structure is 100 nm and the outer diameter is 170 nm, two-phase coupling interface is obvious, and the length of the nanofiber can reach 1.8 μm. The magnetic properties of the composites show a decreasing trend after upward, reaching the highest Ms (43 emu/g) and Hc(4524 Oe) at 900 °C, which is better than for other materials with various morphologies such as sheet and particle. The hysteresis loop at 900 °C shows a single-phase-like magnetic characteristic, indicating the existence of effective exchange coupling. This study provides a basis for the preparation of hard-soft nanocomposite ferrite fibers with controlled core-shell structure, excellent exchange coupling and outstanding magnetic properties .
研究领域:
材料科学
·
磁性材料
✓ 已验证
DOI
高影响因子
Journal of Superconductivity and Novel Magnetism
·
2023
·Vol. 36
·期 2
·711-719
·
IF 1.8
Huang Danqiang,Wen Xinchao,Dai Jianfeng,Wang Qing,Liu Hui,Li Zengpeng
In this study, SrFe 12 O 19 @MFe 2 O 4 (M = Co, Ni, Zn) core–shell nanofibers were fabricated by coaxial electrostatic spinning. The composites obtained at an annealing temperature of 900 °C are composed of SrFe 12 O 19 in pure phase and MFe 2 O 4 (M = Co, Ni, Zn) in different spinels. X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscope (TEM) were used to describe the structure and morphology of nanofibers. Magnetic Property Measurement Systems (MPMS) are used to characterize the magnetic properties of nanofibers. Sr@Ni and Sr@Zn fibers all exhibit a unique core–shell structure, while Sr@Co fibers are connected by a lamellar structure. The single-phase hysteresis lines for each composite indicate the presence of exchange coupling effects between the hard/soft magnetic composite phases. The magnetic properties of the composites change as the soft magnetic material in the shell layer changes. Sr@Co has the highest M s (69.43 emu/g) and M r (33.82 emu/g), whereas Sr@Zn has the highest H c (2927 Oe). The switching plant curves indicate that the best exchange coupling of the three groups of samples is for Sr@Co. The magnetic properties of the composites are explained in terms of the nanofiber diameter, the exchange coupling between the two phases, and the nature of the soft magnetic phase itself. It is shown that the exchange coupling of composites is closely related to the type of composite.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 9
·2108
·
IF 3.2
Yangzhou Wang,Qianshuo Wang,Yanhao Dong,Jin Wang,Shu Chen,Zihan Wang,Fei Chen,Guixin Cao,Wei Ren,Jie Li,Wen Wan
Multiband and nodal-like superconductivity (SC) with s- + d-wave pairing symmetry have implied that tetragonal iron sulphide (FeS) is a distinctive testbed for exploring unexpected electronic correlations. In particular, the low-moment disordered static magnetism originating from the Fe moment leads to the possibility of the coexistence of magnetic orders (MOs) in the superconducting ground state via the tuning of electronic configurations. Here, guided by density functional theory (DFT) calculations, we found that slightly substitutionally doped chromium (Cr) atoms in tetragonal FeS single crystals can induce both considerable d-orbital reconstruction around the Fermi surface and a local magnetic moment of 2.4µBat each doping site, which could highly modulate the SC ground states of the host. On this basis, a clear magnetic transition and reduced anisotropy of SC were experimentally observed. In particular, SC can survive with a doping content below 0.05. This coexistence of SC and MOs suggests strong spin correlations between Cr dopants and the host through exchange coupling. Further, an electronic temperature-related phase diagram of FeS with Cr doping contents from 0 to 0.07 is also provided. These results demonstrate that the continuous injection of local moments can be a controllable method to use to tune collective orders in unconventional iron-based superconductors.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Optical Materials
·
2016
·Vol. 4
·期 5
·798-806
·
IF 5.359
Enhai Song,Zitao Chen,Ming Wu,Sha Ding,Shi Ye,Shifeng Zhou,Qinyuan Zhang
In contrast to well-known multiple and fixed upconversion (UC) emission bands from lanthanide (Ln 3+ ) ions activated luminescent materials, room temperature wavelength-tunable single-band UC emissions are designed and demonstrated in Ln 3+ ions/transition metal Yb 3+ /Mn 2+ codoped fluoride perovskites ABF 3 (A = K + , Rb + , and Cs + ; B = Mg 2+ , Zn 2+ , and Cd 2+ ). Upon 976 nm laser excitation, the perovskites ABF 3 :Yb 3+ , Mn 2+ exhibit intense single band UC emission centered at 550–610 nm depending on the substitution of the A + and / or the B 2+ species in ABF 3 . Crystal structure and luminescent properties analysis show that the UC emission should originate from the transitions of super-exchange coupled Yb 3+ –Mn 2+ pair. The Stokes and UC emission properties, UC luminescence decay behaviors, as well as temperature dependent UC emission properties of ABF 3 :Yb 3+ , Mn 2+ are investigated and discussed in detail. The intense room (or high) temperature UC emission and ultralong UC decay lifetimes (≈25–45 ms) clearly reveal that the perovskites ABF 3 :Yb 3+ , Mn 2+ can be potentially applied in the fields of time-resolved luminescence imaging, lighting, and solid state lasers.
研究领域:
材料科学
·
光学材料
·
无机化学
·
光子学
·
固体物理
✓ 已验证
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2025
·
IF 7
Hui Zhu,Cheng Zhou,Siying Li,Huanhuan Chen,Xuan Shi,Yanyue Li,Pingzhi Zhang,Wei Li,Maxim S. Molokeev,Andrey O. Zolotov,Jing Wang,Zhi Zhou,Mao Xia
Introducing large-radius cations usually causes structural relaxation, leading to a spectral redshift and low optical performance in Cr3+-activated phosphors. Here, MNAl10O17:Cr3+ phosphors are synthesized, and the substitution of large-radius cations induces the abnormal lattice shrinkage of the N site and atomic site splitting of the M site due to the unique hexaaluminate structure, further distinctly improving luminescent properties. To investigate the university of atomic site splitting, a series of phosphors, Na2(1–m)K2mAl10.8O17:0.2Cr3+ and Gd1–nLanMgAl10.8O19:0.2Cr3+, are synthesized, and the variation of their luminescent properties conforms to the expected rule. Finally, Ga3+ ions are introduced to improve the luminescence efficiency. Internal/external quantum efficiencies of the optimal sample are 98.1 and 65.8%, respectively. Meanwhile, an anomalous spectral blueshift indicates the existence of Cr3+–Cr3+ exchange coupling pairs, and a comparative analysis of similar cases is conducted to provide some insights into the luminescence of coupling pairs.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Cijun Shuai,Chong Lin,Chongxian He,Wei Tan,Shuping Peng,Wenjing Yang
Bone implant-associated bacterial infection is a common cause of transplant failure. Chemodynamic therapy (CDT) has significant antibacterial efficacy by producing reactive oxygen species (ROS). However, the ROS permeability is restricted by the natural barrier of bacterial biofilms. Herein, a hard-soft magnetic biphasic nanoparticle (CF@MF) was synthesized by in-situ growth of the soft MnFe 2 O 4 shell on the hard CoFe 2 O 4 core. Then, the CF@MF was incorporated into poly- l -lactide powders to prepare porous scaffolds by selective laser sintering. The scaffold exhibited superior magnetothermal conversion efficiency, which was attributed to the interfacial exchange coupling of CF@MF. Importantly, the scaffold effectively dispersed biofilms by magnetothermal therapy (MTT), favoring numerous ROS pre-generated by CDT to enter the interior to kill bacteria. This study provided a synergistic MTT/CDT strategy to eradicate deep bacterial infections in biomedical application.
研究领域:
生物医学工程
·
材料科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Semiconductors
·
2020
·Vol. 41
·期 12
·122501
·
IF 0
Zhiguo Sun,Bo Cai,Xi Chen,Wenxian Wei,Xiaoming Li,Dandan Yang,Cuifang Meng,Ye Wu,Haibo Zeng
The possibility to induce a macroscopic magnetic moment in lead halide perovskites (LHPs), combined with their excellent optoelectronic properties, is of fundamental interest and has promising spintronic applications. However, these possibilities remain an open question in both theory and experiment. Here, theoretical and experimental studies are performed to explore ferromagnetic states in LHPs originated from lattice defects. First-principle calculations reveal that shallow-level Br vacancies in defective CsPbBr3 can produce spin-splitting states and the coupling between them leads to a ferromagnetic ground state. Experimentally, ferromagnetism at 300 K is observed in room-temperature synthesized CsPbBr3 nanocrystals, but is not observed in hot-injection prepared CsPbBr3 quantum dots and in CsPbBr3 single crystals, highlighting the significance played by vacancy defects. Furthermore, the ferromagnetism in the CsPbBr3 nanocrystals can be enhanced fourfold with Ni2+ ion dopants, due to enhancement of the exchange coupling between magnetic polarons. Room-temperature ferromagnetism is also observed in other LHPs, which suggests that vacancy-induced ferromagnetism may be a universal feature of solution-processed LHPs, which is useful for future spintronic devices.
研究领域:
材料科学
·
凝聚态物理
·
自旋电子学
✓ 已验证
DOI
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