Browsing by Author "Jin, H"

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    Magnetic structure and Kondo lattice behavior in CeVGe3: an NMR and neutron scattering study
    (American Physical Society, 2023-09-28) Chaffey, C; Wu, HC; Jin, H; Sherpa, P; Klavins, P; Avdeev, M; Aji, S; Shimodate, R; Nawa, K; Sato, TJ; Taufour, V; Curro, NJ
    We present nuclear magnetic resonance (NMR), neutron diffraction, magnetization, and transport measurements on a single crystal and powder of CeVGe3. This material exhibits heavy fermion behavior at low temperatures, accompanied by antiferromagnetic (AFM) order below 5.8 K. We find that the magnetic structure is incommensurate with AFM helical structure, characterized by a magnetic modulated propagation vector of (0,0,0.49) with in-plane moments rotating around the c axis. The NMR Knight shift and spin-lattice relaxation rate reveal a coherence temperature T∗∼15K, and the presence of significant antiferromagnetic fluctuations reminiscent of the archetypical heavy fermion compound CeRhIn5. We further identify a metamagnetic transition above Hm∼2.5T for magnetic fields perpendicular to c. We speculate that the magnetic structure in this field-induced phase consists of a superposition with both ferromagnetic and antiferromagnetic components, which is consistent with the NMR spectrum in this region of the phase diagram. Our results thus indicate that CeVGe3 is a hexagonal structure analog to tetragonal CeRhIn5. ©2023 American Physical Society.
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    A novel graphene oxide wrapped Na2Fe2(SO4)3/C cathode composite for long life and high energy density sodium‐ion batteries
    (Wiley, 2018-08-06) Chen, MZ; Cortie, DL; Hu, Z; Jin, H; Wang, S; Gu, QF; Hua, WB; Wang, E; Lai, WH; Chen, L; Chou, SL; Wang, XL; Dou, SX
    The cathode materials in the Na‐ion battery system are always the key issue obstructing wider application because of their relatively low specific capacity and low energy density. A graphene oxide (GO) wrapped composite, Na2Fe2(SO4)3@C@GO, is fabricated via a simple freeze‐drying method. The as‐prepared material can deliver a 3.8 V platform with discharge capacity of 107.9 mAh g−1 at 0.1 C (1 C = 120 mA g−1) as well as offering capacity retention above 90% at a discharge rate of 0.2 C after 300 cycles. The well‐constructed carbon network provides fast electron transfer rates, and thus, higher power density also can be achieved (75.1 mAh g−1 at 10 C). The interface contribution of GO and Na2Fe2(SO4)3 is recognized and studied via density function theory calculation. The Na storage mechanism is also investigated through in situ synchrotron X‐ray diffraction, and pseudocapacitance contributions are also demonstrated. The diffusion coefficient of Na+ ions is around 10−12–10−10.8 cm2 s−1 during cycling. The higher working voltage of this composite is mainly ascribed to the larger electronegativity of the element S. The research indicates that this well‐constructed composite would be a competitive candidate as a cathode material for Na‐ion batteries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA.