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Synthesis and magnetic properties of single-crystalline Na2-xMn8O16 nanorods.

Lan C, Gong J, Liu S, Yang S - Nanoscale Res Lett (2011)

Bottom Line: The synthesis of single-crystalline hollandite-type manganese oxides Na2-xMn8O16 nanorods by a simple molten salt method is reported for the first time.The magnetic measurements indicated that the nanorods showed spin glass behavior and exchange bias effect at low temperatures.The low-temperature magnetic behaviors can be explained by the uncompensated spins on the surface of the nanorods.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanjing National Laboratory of Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, 210093, China. sgyang@nju.edu.cn.

ABSTRACT
The synthesis of single-crystalline hollandite-type manganese oxides Na2-xMn8O16 nanorods by a simple molten salt method is reported for the first time. The nanorods were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and a superconducting quantum interference device magnetometer. The magnetic measurements indicated that the nanorods showed spin glass behavior and exchange bias effect at low temperatures. The low-temperature magnetic behaviors can be explained by the uncompensated spins on the surface of the nanorods.

No MeSH data available.


Related in: MedlinePlus

Temperature dependence of magnetization of Na2-xMn8O16 nanorods for ZFC and FC measurements under a magnetic field of 500 Oe. The inset shows the inverse magnetization versus temperature. Solid line represents linear fit between 90 and 300 K.
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Figure 3: Temperature dependence of magnetization of Na2-xMn8O16 nanorods for ZFC and FC measurements under a magnetic field of 500 Oe. The inset shows the inverse magnetization versus temperature. Solid line represents linear fit between 90 and 300 K.

Mentions: The magnetic properties of the Na2-xMn8O16 nanorods were explored. Figure 3 shows the temperature-dependent magnetization curves of the nanorods in zero-field-cooled (ZFC) and field-cooled (FC) processes with an applied magnetic field of 500 Oe. The ZFC magnetization curve shows a sharp peak near 19 K (TB) and an evident separation from the FC curve below TB, suggesting a spin-glass-like behavior at low temperatures [16,19-21]. Such behavior can be attributed to uncompensated surface spins in the 1D nanostructures [16,19-21]. The linear fit for the temperature dependence of the inverse magnetization shows that the product exhibits Curie-Weiss behavior above about 90 K and gives an extrapolated Curie-Weiss temperature (θ) of about -440 K as shown in the inset of Figure 3. The large negative Curie-Weiss temperature indicates the AFM interactions in Na2-xMn8O16 are very strong.


Synthesis and magnetic properties of single-crystalline Na2-xMn8O16 nanorods.

Lan C, Gong J, Liu S, Yang S - Nanoscale Res Lett (2011)

Temperature dependence of magnetization of Na2-xMn8O16 nanorods for ZFC and FC measurements under a magnetic field of 500 Oe. The inset shows the inverse magnetization versus temperature. Solid line represents linear fit between 90 and 300 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211180&req=5

Figure 3: Temperature dependence of magnetization of Na2-xMn8O16 nanorods for ZFC and FC measurements under a magnetic field of 500 Oe. The inset shows the inverse magnetization versus temperature. Solid line represents linear fit between 90 and 300 K.
Mentions: The magnetic properties of the Na2-xMn8O16 nanorods were explored. Figure 3 shows the temperature-dependent magnetization curves of the nanorods in zero-field-cooled (ZFC) and field-cooled (FC) processes with an applied magnetic field of 500 Oe. The ZFC magnetization curve shows a sharp peak near 19 K (TB) and an evident separation from the FC curve below TB, suggesting a spin-glass-like behavior at low temperatures [16,19-21]. Such behavior can be attributed to uncompensated surface spins in the 1D nanostructures [16,19-21]. The linear fit for the temperature dependence of the inverse magnetization shows that the product exhibits Curie-Weiss behavior above about 90 K and gives an extrapolated Curie-Weiss temperature (θ) of about -440 K as shown in the inset of Figure 3. The large negative Curie-Weiss temperature indicates the AFM interactions in Na2-xMn8O16 are very strong.

Bottom Line: The synthesis of single-crystalline hollandite-type manganese oxides Na2-xMn8O16 nanorods by a simple molten salt method is reported for the first time.The magnetic measurements indicated that the nanorods showed spin glass behavior and exchange bias effect at low temperatures.The low-temperature magnetic behaviors can be explained by the uncompensated spins on the surface of the nanorods.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanjing National Laboratory of Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing, 210093, China. sgyang@nju.edu.cn.

ABSTRACT
The synthesis of single-crystalline hollandite-type manganese oxides Na2-xMn8O16 nanorods by a simple molten salt method is reported for the first time. The nanorods were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and a superconducting quantum interference device magnetometer. The magnetic measurements indicated that the nanorods showed spin glass behavior and exchange bias effect at low temperatures. The low-temperature magnetic behaviors can be explained by the uncompensated spins on the surface of the nanorods.

No MeSH data available.


Related in: MedlinePlus