The hopping mechanism in the regio-random poly (3-hexylthiophene-2,5-diyl) was investigated through study on the diffusion rate of the charge carrier transport from the data of Longitudinal Field ...(LF) muon-spin-relaxation measurements. Values of the parallel and perpendicular diffusion rate were calculated following the methods applied in NMR. It is found that diffusion rate along the polymer chain slowly decreases from low to high temperatures, while diffusion rate perpendicular to the polymer chain rises significantly from low to high temperatures.
A series of single-phase samples with BaFe(12–2x) SnxZnxO19 (x = 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.5, 0.7, and 1.0) compositions were successfully fabricated using a mechanical alloying ...technique. The ionic positions Zn2+ and Sn4+ occupy the same site as the Fe3+ions occupying tetrahedral and octahedral sites, respectively. Because the radius of Zn2+ and Sn4+ each is greater than that of Fe3+ the lattice parameters and the unit cell volume increased linearly with an increase of x. The co-substitution of Zn2+ and Sn4+ ions to Fe3+ in the main phase of BaFe12O19 changed the magnetic properties of the sample. Both Zn2+ and Sn4+ substituting ions reduced the magneto-crystalline anisotropy constant of the main phase from 2.3 × 106 erg/cc at x = 0.05 to 0.89 × 106 erg/cc at x = 1.0. This reduction, reduced coercivity from 16.34 kOe to 0.47 kOe. The saturation magnetization of the single-phase samples was not significantly decreased. All BaFe(12–2x) SnxZnxO19 samples were capable of absorbing the electromagnetic wave in the x-band frequency range with a single absorption peak. The best reflection loss (RL) of -28.1 dB with the largest bandwidth of 3.1 GHz was obtained in a single-phase sample with a composition of x = 0.35, having an impedance (Zin = 51.54-j3. 69 Ω) close to Zo (50 Ω).
Display omitted
Rare-earth double perovskite oxides have intriguing magnetocaloric properties at cryogenic temperatures. In this study, Ho
2
NiMnO
6
and Ho
2
CoMnO
6
were synthesized using the sol-gel method, which ...crystallized in a monoclinic structure in the
P
2
1
/
n
space group. The magnetic phase transition was observed at 81.2 K for Ho
2
NiMnO
6
and 73.5 K for Ho
2
CoMnO
6
. The presence of a paramagnetic matrix and short-range ferromagnetic clusters causes magnetic disorder in these double perovskites, resulting in Griffiths phase formation. The Arrott plot confirms that compounds undergo second-order phase transition. At an applied magnetic field of 5 T, the maximum magnetic entropy change (−Δ
S
) for the studied compounds is 1.7 and 2.2 J kg
−1
K
−1
, respectively. The transition metals Ni and Co in a double perovskite cause lattice distortion in the structural parameters and oxidation states of manganese (Mn
3+
/Mn
4+
), which changes the magnetic and magnetocaloric properties. The quantitative approach provides a systematic study of magnetocaloric properties of the rare earth double perovskite compounds with ferromagnetic 3d transition elements.
We report systematic experimental investigation of nanocrystalline Ho
2
NiMnO
6
and Ho
2
CoMnO
6
compounds by chemical method. The structural and magnetic, and magnetocaloric properties have been studied for their cryogenic temperature application.
Recently, hybrid solar cell, which is a combination of organic and inorganic material, has been developed to produce better performance especially in power conversion efficiency of solar cell. ...Organic material based on conjugated polymer such as Poly(3-hexylthiophene) (P3HT) attracted much attention because P3HT shows the highest hole mobility among the series of Poly(3-alkylthiophene). On the other hand, it is well known that ZnO nanoparticles are an inorganic material with high electron mobility that can be acted as electron acceptor to dissociate excitons formed in organic material. The existence of ZnO nanoparticles in active layer of solar cell will lead to dissociation of excitons in P3HT via rapid electron transfer to ZnO. To understand the mechanism of charge carrier transport in blend of P3HT and ZnO nanoparticles, we have been conducted an experiment using muon spin relaxation (µSR) at low temperature of 10 K with variation of longitudinal field from 2 to 395 mT. We also investigated the effect of light irradiation to the charge carrier transport in blend of P3HT and ZnO nanoparticles. Without light irradiation, it is clearly observed that depolarization rate (λ) was proportional to linier field of H-0.5, indicating one-dimensional intra-chain transport of charge carrier. With light irradiation, it is found that asymmetry data changed slightly indicating the trace of any changing of charge carrier transport to increase in the amount of exciton in samples causing by light irradiation.
This study aims to determine the effect of synthetic stirring rate on the diffraction and magnetization properties of Fe3O4 nanoparticles. Materials made from natural iron sand were synthesized using ...the co-precipitation method with variations in stirring rate 270 to 470 rpm. At stirring up to 370 rpm (R3), the crystalline size of Fe3O4 decreases. Increasing the stirring rate caused the lattice parameters to decrease in the range of 8.3 Ao and the X-ray density to increase in the range of 5.0 g cm-3. The structure formed indicates that the sample contains 100% magnetite nanoparticles without any contaminants. The magnetite nanoparticles in this experiment with the smallest crystal size of 4.156 nm and the Ms value of 20.67 emu g-1 with a Hc value close to zero superparamagnetic, have the potential for future biomedical applications.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
