Magnetic pole enhanced inductively coupled plasmas （MaPE-ICPs） are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optic...Magnetic pole enhanced inductively coupled plasmas （MaPE-ICPs） are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a MaPE-ICP Ar-Na/He mixture plasma. Electron density （ne） and temperature （Te）, excitation temperature （Texc）, plasma potential （Vp）, skin depth （6） and the evolution of the electron energy probability function （EEPF） are reported as a function of radiofrequency （RF） power, pressure and argon concentration in the mixture. It is observed that ne increases while Te decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail＇ of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-Maxwellian＇ distribution at low RF powers and higher pressure in a pure N2 discharge. However, it evolves into a ‘Maxwellian＇ distribution at RF powers greater than 70 W for pure N2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-Maxwellian＇ EEPF is examined. The temperature of the low-energy electron group TL shows a decreasing trend with argon addition until the ‘thermalization＇ of the two temperatures occurs, while the temperature of high-energy electrons Ta decreases continuously.展开更多
The effect of particle size distribution on the field and temperature dependence of the hysteresis loop features like coercivity（HC）, remanence（MR）, and blocking temperature（TB） is simulated for an ensemble of s...The effect of particle size distribution on the field and temperature dependence of the hysteresis loop features like coercivity（HC）, remanence（MR）, and blocking temperature（TB） is simulated for an ensemble of single domain ferromagnetic nanoparticles with uniaxial anisotropy. Our simulations are based on the two-state model for T 〈 TB and the metropolis Monte-Carlo method for T 〉 TB. It is found that the increase in the grain size significantly enhances HC and TB. The presence of interparticle exchange interaction in the system suppresses HC but causes MRto significantly increase.Our results show that the parameters associated with the particle size distribution（D（d,δ）） such as the mean particle size d and standard-deviation δ play key roles in the magnetic behavior of the system.展开更多
基金aided by the Higher Education Commission(HEC)under the NRPU Research Project no.2997/R&D/14 COMSATS Institute of Information TechnologyHEC Research Project no.20-2002(R&D)Quaid-i-Azam University
文摘Magnetic pole enhanced inductively coupled plasmas （MaPE-ICPs） are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a MaPE-ICP Ar-Na/He mixture plasma. Electron density （ne） and temperature （Te）, excitation temperature （Texc）, plasma potential （Vp）, skin depth （6） and the evolution of the electron energy probability function （EEPF） are reported as a function of radiofrequency （RF） power, pressure and argon concentration in the mixture. It is observed that ne increases while Te decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail＇ of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-Maxwellian＇ distribution at low RF powers and higher pressure in a pure N2 discharge. However, it evolves into a ‘Maxwellian＇ distribution at RF powers greater than 70 W for pure N2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-Maxwellian＇ EEPF is examined. The temperature of the low-energy electron group TL shows a decreasing trend with argon addition until the ‘thermalization＇ of the two temperatures occurs, while the temperature of high-energy electrons Ta decreases continuously.
文摘The effect of particle size distribution on the field and temperature dependence of the hysteresis loop features like coercivity（HC）, remanence（MR）, and blocking temperature（TB） is simulated for an ensemble of single domain ferromagnetic nanoparticles with uniaxial anisotropy. Our simulations are based on the two-state model for T 〈 TB and the metropolis Monte-Carlo method for T 〉 TB. It is found that the increase in the grain size significantly enhances HC and TB. The presence of interparticle exchange interaction in the system suppresses HC but causes MRto significantly increase.Our results show that the parameters associated with the particle size distribution（D（d,δ）） such as the mean particle size d and standard-deviation δ play key roles in the magnetic behavior of the system.
