Self-template formation and properties study of Cr<sub>2</sub>O<sub>3</sub>nanoparticle tubes

Lei, Shuijin; Peng, Xiaomin; Liang, Zhihong; Li, Xiuping; Wang, Qianqian; Cheng, Baochang; Xiao, Yanhe; Zhou, Lang

doi:10.1039/c1jm13127c

Cited by 36 publications

(21 citation statements)

References 42 publications

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“…39 Briey, the in situ reduction by EG and the self-template of the potassium rare-earth chromates should play critical roles in the formation of the hollow structures. 39 Briey, the in situ reduction by EG and the self-template of the potassium rare-earth chromates should play critical roles in the formation of the hollow structures.…”

Section: Comprehensive Morphology Analysis-growth Mechanismmentioning

confidence: 99%

General synthesis of rare-earth orthochromites with quasi-hollow nanostructures and their magnetic properties

et al. 2013

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Rare-earth orthochromites are extremely interesting because of their potential applications as multifunctional materials. However, it is still a great challenge for the general synthesis of nanostructured full rare-earth orthochromites series. Here, a facile and versatile solvothermal reduction strategy is successfully employed in the preparation of rare-earth chromites with quasi-hollow nanostructures. X-ray diffraction data show that all the products have the orthorhombic perovskite structure. The electron microscopy analysis reveals that the morphology of the product is seriously affected by the rare-earth ionic radius. Tube-like and vesicle-like structures can be formed for the larger and smaller rare-earth cationic radii, respectively. The experimental results suggest that the roomtemperature precursors of potassium rare-earth chromates serve as a self-template for the in situ reduction and formation of rare-earth orthochromites hollow structures. The magnetization studies demonstrate that all the products, as it would be expected, undergo a magnetic transition from paramagnetic to antiferromagnetic phase at the Néel temperature (T N1 ) attributed to Cr 3+ -Cr 3+ exchange and this critical temperature goes up linearly with an increase in the rare-earth ionic radius.Additionally, some samples exhibit a variety of fancy magnetic properties, including thermal hysteresis suggesting a first-order magnetic transition, magnetization reversal due to the antiparallel polarization of the R 3+ paramagnetic moments by the Cr 3+ canted antiferromagnetic ones, and magnetic exchange bias related to the spin reorientation transition of the Cr 3+ magnetic moments. † Electronic supplementary information (ESI) available: XRD patterns and SEM images of the typical room-temperature intermediates; TEM images of the typical 1200 C annealing sample; SEM images of LaCrO 3 , PrCrO 3 , NdCrO 3 and SmCrO 3 before and aer annealing; summary of the magnetic data based on the temperature dependence of the magnetization for all samples. See

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Section: Comprehensive Morphology Analysis-growth Mechanismmentioning

confidence: 99%

General synthesis of rare-earth orthochromites with quasi-hollow nanostructures and their magnetic properties

et al. 2013

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“…The peak at about 365 nm is associated with the conventional band gap ( 3 eV) of α-Cr 2 O 3 [13]. The absorption peaks at around 460 nm and 600 nm correspond to 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g 3d 3 electronic transitions of octahedral Cr 3+ ions [22]. It is difficult to classify whether the peaks are due to direct or indirect electronic transitions for wide band gap semiconductors, like α-Cr 2 O 3 .…”

Section: Optical Absorption Propertiesmentioning

confidence: 99%

Doping of Ga in antiferromagnetic semiconductor α-Cr2O3 and its effects on magnetic and electronic properties

Bhowmik

Siva

Ranganathan

et al. 2017

Journal of Magnetism and Magnetic Materials

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The samples of Ga doped Cr 2 O 3 oxide have been prepared using chemical co-precipitation route.X-ray diffraction pattern and Raman spectra have confirmed rhombohedral crystal structure with space group R3 C. Magnetic measurement has indicated the dilution of antiferromagnetic (AFM) spin order in Ga doped α-Cr 2 O 3 system oxide, where the AFM transition temperature of bulk α-Cr 2 O 3 oxide at about 320 K has been suppressed and ferrimagnetic behavior is observed from the analysis of the temperature dependence of magnetization data below 350 K. Apart from Ga doping effect, the spin freezing (50 K-70 K) and superparamagnetic behavior of the surface spins at lower temperatures, typically below 50 K, have been exhibited due to nano-sized grains of the samples. All the samples showed non-linear current-voltage (I-V) characteristics. However, I-V characteristics of the Ga doped samples are remarkably different from α-Cr 2 O 3 sample. The I-V curves of Ga doped samples have exhibited many unique electronic properties, e.g., bi-stable (low resistance-LR and high resistance-HR) electronic states and negative differential resistance (NDR). Optical absorption spectra revealed three electronic transitions in the samples associated with band gap energy at about 2.67-2.81 eV, 1.91-2.11 eV, 1.28-1.35 eV, respectively. 2 Key Words: Magnetic semiconductor; tuning of band gap; negative differential resistance; I-V loop, bi-stable electronic state.

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“…The occurrence of peak at 350 nm suggests the presence of Cr 4þ ion in the species which supported the XPS result. Whereas, the two peaks at 455 nm and 600 nm reflect the d 3 electronic transition of Cr 3þ ion attributing to 4 A 2g / 4 T 1g and 4 A 2g / 4 T 2g , respectively [41]. Fig.…”

Section: Resultsmentioning

confidence: 98%

Solvothermal synthesis of Cr2O3 nanocubes via template-free route

Roy

Ghosh

Naskar

2015

Materials Chemistry and Physics

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Self-template formation and properties study of Cr₂O₃nanoparticle tubes

Cited by 36 publications

References 42 publications

General synthesis of rare-earth orthochromites with quasi-hollow nanostructures and their magnetic properties

General synthesis of rare-earth orthochromites with quasi-hollow nanostructures and their magnetic properties

Doping of Ga in antiferromagnetic semiconductor α-Cr2O3 and its effects on magnetic and electronic properties

Solvothermal synthesis of Cr2O3 nanocubes via template-free route

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Self-template formation and properties study of Cr2O3nanoparticle tubes

Cited by 36 publications

References 42 publications

General synthesis of rare-earth orthochromites with quasi-hollow nanostructures and their magnetic properties

General synthesis of rare-earth orthochromites with quasi-hollow nanostructures and their magnetic properties

Doping of Ga in antiferromagnetic semiconductor α-Cr2O3 and its effects on magnetic and electronic properties

Solvothermal synthesis of Cr2O3 nanocubes via template-free route

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Self-template formation and properties study of Cr₂O₃nanoparticle tubes