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Effect of nd doping on Nanosized Mn-Zn Ferrite

Journal of Rare Earths 2005年第S1期23卷 288-292页

作者：郭秀盈肖谧吴霞宛张之圣 School of Electronics and Information Engineering Tianjin University Tianjin 300072 China

Nanosized Mn-Zn ferrite doped with nd (Mn_ 0.6Zn_ 0.4nd_xFe_ 2-xO_4) were fabricated by hydrothermal precipitation route and studied by XRD, TEM, DSC and VSM. The effects of nd doping on manganese zinc ferrites were discussed. The results show that the samples with a small amount of nd doping are spinel crystal structure and uniformly nanosized particles with little aggregation. DSC analysis of Mn_ 0.6Zn_ 0.4Fe_2O_4 and Mn_ 0.6Zn_ 0.4nd_ 0.06Fe_ 1.94O_4 samples both present two exothermic peaks ascribed to the redistribution of Mn 2+, Zn 2+ and Fe 3+ ions in the two sub-lattices (tetrahedral (A) and octahedral (B) sites), and the oxidation of Mn 2+-ions at higher temperatures respectively. The saturation magnetization (M_s) for Mn_ 0.6Zn_ 0.4nd_xFe_ 2-xO_4 ferrites increase with (x) up to 0.06 and decrease for higher concentrations. And supermagnetic behavior was observed at 25 ℃ in the M-H loops of Mn_ 0.6Zn_ 0.4Fe_2O_4 and Mn_ 0.6Zn_ 0.4nd_ 0.06Fe_ 1.94O_4 samples for their extremely small sizes.

关键词： Mn-Zn ferrite hydrothermal nd doping superparamagnetic

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Magnetocaloric properties of nd-doped Gd5Si4 microparticles and nanopowders

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Chinese Physics B 2024年第11期33卷 396-402页

作者： Kaiyang Zhang Huanhuan Wang Ying Wang Tao Wang School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China

The preparation of materials with enhanced magnetocaloric properties is crucial for magnetic refrigeration. In thisstudy, nd-doped Gd5Si4 microparticles and nanomaterials were synthesized using the reduction–diffusion method. Theimpact of nd doping with varying compositions on the structure and entropy change properties of the materials was *** Curie temperatures of both the micron- and nano-sized materials ranged from 190 K to 210 K, which were lowerthan previously reported values. Micron-sized samples doped with 1% nd exhibited superior magnetocaloric properties,demonstrating a maximum entropy change of 4.98 J·kg^(-1)·K^(-1) at 5 T, with an entropy change exceeding 4 J·kg^(-1)·K^(-1)over a wide temperature range of approximately 70 K. Conversely, the nanomaterials had broader entropy change peaks butlower values. All samples exhibited a second-order phase transition, as confirmed by the Arrott plots.

关键词： magnetocaloric Gd5Si4 nd doping reduction-diffusion method

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Hydrophilic and photocatalytic activities of nd-doped titanium dioxide thin films

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Transactions of Nonferrous Metals Society of China 2015年第8期25卷 2601-2607页

作者：杜军顾馨吴其刘娇郭海志邹建国南昌大学环境与化学工程学院鄱阳湖生态与资源再利用教育部重点实验室南昌330031

The nd-doped TiO2 thin films with higher hydrophilic and photocatalytic activities were prepared on glass slides by an acid-catalyzed sol？gel method. The effects of nd doping on crystalline phase, surface composition and optical property were investigated by means of techniques such as X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FT-IR）, optical contact angle tester and UV-Vis spectroscopy. The results show that nd doping obviously influences the hydrophilic and photocatalytic activities of TiO2thin films. nd doping could cause the TiO2 lattice distortion, inhibit phase transition from anatase to rutile, cause red shift of the absorption spectrum edge, produce hydroxyl radicals （·OH）, and accelerate surface hydroxylation, which result in a significant improvement in the hydrophilicity and photoreactivity of nd-doped TiO2 thin films. When the content of nd is 0.1% （mass fraction）, TiO2 thin films achieve the smallest grain size （about 15 nm）, and the hydrophilic and photocatalytic activities of TiO2 thin film reach the maximum, the contact angle is only 8.1°, and 92% of methylene blue is finally degraded. Moreover, the modification mechanism of nd doping was also discussed.

关键词： nd doping sol-gel method hydrophilicity photocatalysis

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