Cr/SmCo/Cr thin films with Sm concentration of 37.7 at.% were deposited on glass substrates by magnetron sputtering. Measurement of magnetic properties showed that the SmCo film possessed good magnetic anisotropy, a h...Cr/SmCo/Cr thin films with Sm concentration of 37.7 at.% were deposited on glass substrates by magnetron sputtering. Measurement of magnetic properties showed that the SmCo film possessed good magnetic anisotropy, a high coercivity of 3019 kA/m and low magnetic exchange coupling. Microstructure analysis showed that crystallized SmCo5 magnetic phase, non-magnetic SmCo2 phase and Sm2Co7 phase co-existed in the film. The non-magnetic SmCo2 phase might function as isolator of SmCo grains, leading to a decrease of magnetic exchange coupling. Moreover, a Cr2O3 oxide layer which could protect the SmCo layer from oxidation formed at the surface of the Cr cap layer.展开更多
Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivit...Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivity decreases with increasing of temperature. The remanence decreases with increasing the temperature from 26 to 100℃, and then increases with continuously increasing the temperature from 100 to 150℃. The reduced remanence increases with increasing the temperature.展开更多
SmxCo5(x = 1.3, 0.7, 0.4) thin films were prepared by magnetron co-sputtering technique. The samples were annealed at 723 K under Ar atmosphere. The annealed time was chosen as 30 min. The hysteresis loops of the samp...SmxCo5(x = 1.3, 0.7, 0.4) thin films were prepared by magnetron co-sputtering technique. The samples were annealed at 723 K under Ar atmosphere. The annealed time was chosen as 30 min. The hysteresis loops of the samples were measured under the ac applied magnetic field with the period Tp(2πω) , H(t) = H0sin(ωt), by vibrating sample magnetometer (VSM). The experimental results indicate that, (1) the average hysteresis loop areas as functions of the values of H0 andωdisplay a power scaling law with the exponents, A = A0 + H0αωβ; (2) the x composition of SmxCo5 film has evident effect on the scaling behavior and magnetic properties; (3) the anisotropy scaling exponents exist clearly in the anisotropy SmxCo5 thin films. Moreover, the scaling behavior of the anisotropy magnetic film was also simulated with Monte Carlo method. The simulated results are consistent with the experimental fact.展开更多
SmCo based films with excellent intrinsic magnetic properties have promising applications in micro-electro-mechanical system(MEMS).However,due to the complexity of phase composition and uncontrollable crystallization ...SmCo based films with excellent intrinsic magnetic properties have promising applications in micro-electro-mechanical system(MEMS).However,due to the complexity of phase composition and uncontrollable crystallization degree of SmCo hard magnetic phase in the film,both the coercivity(Hc)and remanence(Mr)of films are difficult to enhance simultaneously.In this paper,SmCo based films were deposited with a Cr underlayer and capping layer on single crystal Si substrates via magnetron sputtering process.The effects of annealing parameters and Sm/Co atomic ratio on the phase structure and coercivity of films are discussed.By adjusting the Sm/Co atomic ratio from 1:5 to 1:4,Co soft magnetic phase disappears and the single phase SmCo5 is obtained,leading to the increase of coercivity of the films from 30 to 34 kOe.The influence of deposition temperature and Cu doping on magnetic properties of SmCo based films was investigated.When the deposition temperature increases from room temperature to 250℃,the coercivity will further increase from 34 to 51 kOe.However,a severe kink is observed in the demagnetization curves due to the poor exchanged coupling.An analysis of transmission electron microscopy(TEM)confirms that the average size of non-hard magnetic amorphous phase exceeds the effective exchanged coupling length of SmCo5,which contributes to the decoupling and low remanence ratio.Therefore,doping Cu and applying a post-annealing process can significantly improve the crystallization degree of the films.Both the coercivity and the remanence ratio of the demagnetization curves are greatly enhanced.We propose a plausible strategy to prepare the SmCo based films with high coercivity and remanence ratio by temperature and chemical optimization,which can be utilized in high performed MEMS devices.展开更多
基金Project supported by the National Natural Science Foundation of China (50671008,50871014,50831002)
文摘Cr/SmCo/Cr thin films with Sm concentration of 37.7 at.% were deposited on glass substrates by magnetron sputtering. Measurement of magnetic properties showed that the SmCo film possessed good magnetic anisotropy, a high coercivity of 3019 kA/m and low magnetic exchange coupling. Microstructure analysis showed that crystallized SmCo5 magnetic phase, non-magnetic SmCo2 phase and Sm2Co7 phase co-existed in the film. The non-magnetic SmCo2 phase might function as isolator of SmCo grains, leading to a decrease of magnetic exchange coupling. Moreover, a Cr2O3 oxide layer which could protect the SmCo layer from oxidation formed at the surface of the Cr cap layer.
文摘Sm22Co78/Fe65Co35/Sm22Co78/Fe65Co35 multilayer films were prepared by magnetron sputtering. The temperature dependence of coercivity (Hc), remanence (Mr) and reduced remanence (Mr/Ms) has been measured. The coercivity decreases with increasing of temperature. The remanence decreases with increasing the temperature from 26 to 100℃, and then increases with continuously increasing the temperature from 100 to 150℃. The reduced remanence increases with increasing the temperature.
基金Project supported by the National Key Project for Basic Research of China (20005CB623605)NSF of China ( 10474037)
文摘SmxCo5(x = 1.3, 0.7, 0.4) thin films were prepared by magnetron co-sputtering technique. The samples were annealed at 723 K under Ar atmosphere. The annealed time was chosen as 30 min. The hysteresis loops of the samples were measured under the ac applied magnetic field with the period Tp(2πω) , H(t) = H0sin(ωt), by vibrating sample magnetometer (VSM). The experimental results indicate that, (1) the average hysteresis loop areas as functions of the values of H0 andωdisplay a power scaling law with the exponents, A = A0 + H0αωβ; (2) the x composition of SmxCo5 film has evident effect on the scaling behavior and magnetic properties; (3) the anisotropy scaling exponents exist clearly in the anisotropy SmxCo5 thin films. Moreover, the scaling behavior of the anisotropy magnetic film was also simulated with Monte Carlo method. The simulated results are consistent with the experimental fact.
基金Project supported by the National Key R&D Program of China(2022YFB3505700,2022YFB3807900)National Natural Science Foundation of China(51901079)+2 种基金R&D(Research and Development)Plan in Key Areas of Guangdong Province(SDZX2021002,212021032611700001)Natural Science Foundation of Guangdong Province(2020A1515010736,2021A1515010451)the Guangzhou Municipal Science and Technology Program(202007020008)。
文摘SmCo based films with excellent intrinsic magnetic properties have promising applications in micro-electro-mechanical system(MEMS).However,due to the complexity of phase composition and uncontrollable crystallization degree of SmCo hard magnetic phase in the film,both the coercivity(Hc)and remanence(Mr)of films are difficult to enhance simultaneously.In this paper,SmCo based films were deposited with a Cr underlayer and capping layer on single crystal Si substrates via magnetron sputtering process.The effects of annealing parameters and Sm/Co atomic ratio on the phase structure and coercivity of films are discussed.By adjusting the Sm/Co atomic ratio from 1:5 to 1:4,Co soft magnetic phase disappears and the single phase SmCo5 is obtained,leading to the increase of coercivity of the films from 30 to 34 kOe.The influence of deposition temperature and Cu doping on magnetic properties of SmCo based films was investigated.When the deposition temperature increases from room temperature to 250℃,the coercivity will further increase from 34 to 51 kOe.However,a severe kink is observed in the demagnetization curves due to the poor exchanged coupling.An analysis of transmission electron microscopy(TEM)confirms that the average size of non-hard magnetic amorphous phase exceeds the effective exchanged coupling length of SmCo5,which contributes to the decoupling and low remanence ratio.Therefore,doping Cu and applying a post-annealing process can significantly improve the crystallization degree of the films.Both the coercivity and the remanence ratio of the demagnetization curves are greatly enhanced.We propose a plausible strategy to prepare the SmCo based films with high coercivity and remanence ratio by temperature and chemical optimization,which can be utilized in high performed MEMS devices.
