- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Extreme asymmetry of Néel domain walls in multilayered films of the dilute magnetic semiconductor (Ga,Mn)(As,P)
摘要： We report on unconventional perfectly shaped, fully asymmetric ～90? Néel domain walls in multilayered ?lms of the diluted ferromagnetic semiconductor (Ga,Mn)(As,P) with a stepwise variation of P doping. Our results contradict micromagnetic calculations, which favor symmetric domain walls due to crystallographic anisotropy and stray ?eld energy. We demonstrate that both the puzzling uniaxial in-plane anisotropy in the tetragonal multilayered ?lm and the asymmetry of the domain walls could result from Dzyaloshinskii-Moriya interactions that are enhanced by the multiple sharp interfaces between the layers and from anisotropic nonrelativistic exchange coupling. Our ?nding shows that digital variations of composition during the molecular beam epitaxy can be used to tune the anisotropy and chirality of magnetic multilayers.
关键词： diluted magnetic semiconductor,Dzyaloshinskii-Moriya interactions,magnetic anisotropy,Néel domain walls,molecular beam epitaxy
更新于2025-09-23 15:21:01
-
Oxygen vacancy induced ferromagnetism in ball milled Zn0.97Ni0.03O: Confirmation through electron spin resonance
摘要： Among the semiconducting materials, ZnO is a versatile multifunctional candidate with a direct band gap of 3.37 eV at 300 K and large excitonic binding energy of 60 meV which can be useful for spintronics device applications. ZnO has high solubility for transition metals. The transition metals which have been used for DMS, Ni is the most efficient doping element to improve the electrical, magnetic properties of ZnO. Ni doped ZnO would be a good candidate to achieve ferromagnetic property with a high curie temperature i.e. above the room temperature. In this study, Zn1?xNixO (x = 0.03) powder sample was successfully synthesized by a ball milling technique. The X-ray diffraction analysis confirms the polycrystalline, hexagonal wurzite structure for 3% Ni doped ZnO nanoparticles. The substitution of Ni in the ZnO matrix has been confirmed by micro-Raman analysis with the observation of E2 (High) vibrational mode at 437 cm?1 which refers to the strongest mode of vibration in wurtzite crystal structure. A broadened peak observed at 570 cm?1 informs about the presence of clusters of oxygen vacancies. VSM measurement of the sample shows the ferromagnetic hysteresis loop at room temperature with saturation moment of 9 × 10?5 emu/g. The calculated ‘g’ value of 1.95 from electron spin resonance spectrum suggests that the observed ferromagnetism is due to the oxygen vacancy.
关键词： Diluted magnetic semiconductor,Electron spin resonance,Defects,Ferromagnetism,ZnO,Nanoparticles
更新于2025-09-19 17:13:59
-
Improvement of charge transport for hydrothermally synthesized Cd0.8Fe0.2S over co-precipitation method: A comparative study of structural, optical and magnetic properties
摘要： Here, we have elucidated the structural, optical, magnetic and electrical properties of Cd0.8Fe0.2S which is considered as diluted magnetic semiconductor (DMS). Cd0.8Fe0.2S materials were synthesized using co-precipitation (compound 1) and hydrothermal (compound 2) method. The particle size and the polycrystalline phase of the synthesized materials are significantly influenced by the synthesis procedures. Presence of anti-ferromagnetic coupling confirms the magnetic behavior of materials. The current-voltage (I-V) characteristics exhibit lower barrier height for the device based on compound 2 (0.59 eV) than the other device (0.64 eV). Furthermore, the 19 times enhanced mobility and lesser density of states near the Fermi level for the Al/compound 2/ITO configured device is enlightened by the space charge conduction mechanism. But, the interface resistances of the devices cannot be distinguished by the I-V characteristics. Therefore, we have tackled the problem by simulating the Nyquist plots obtained from impedance spectroscopy. We have fitted the Nyquist plots with the appropriate equivalent circuit and explained the mechanism of charge transport through the Schottky interface. The higher dc conductivity and lower relaxation time of diode fabricated by compound 2 confirm the outcomes obtained from I-V characteristics. The effect of particle size on charge transport was also analyzed.
关键词： Schottky diode characteristics,Diluted magnetic semiconductor,Chemical synthesis,Impedance spectroscopy
更新于2025-09-10 09:29:36