Influence of composition and annealing temperature on structure and magnetic properties of amorphous and nanocrystalline Fe78.4-xCoxSi9B9Nb2.6Cu1 (x=27.4, 40.0, 51.0, 78.4) alloys was investigated by X-ray diffracti...Influence of composition and annealing temperature on structure and magnetic properties of amorphous and nanocrystalline Fe78.4-xCoxSi9B9Nb2.6Cu1 (x=27.4, 40.0, 51.0, 78.4) alloys was investigated by X-ray diffraction (XRD) and the temperature dependence of permeability. According to the initial crystallization temperature (Tx1) from differential scanning calorimetry (DSC) curves of as-quenched amorphous alloys, 490-700 ℃ isothermal annealing was carded out to obtain the characteristic nanocrystalline structure. Furthermore, the soft magnetic properties were measured by temperature evolution of magnetic permeability to obtain the correlation between Co content, annealing temperature and magnetic permeability. The results show that, on the one hand, the annealing temperature exerts a significant effect on phase structure and initial permeability (μi). The higher-temperature (from 550 to 610 ℃) annealed Co content nanocrystalline samples can remain higher μi at elevated temperature. On the other hand, partial substitution Fe by Co can improve the high-temperature magnetic stability;however, the room-temperature permeability of higher Co content alloys decreases obviously at the same time. This phenomenon was analyzed from the viewpoint of the saturation magnetic induction (Bs), magnetic anisotropy (〈K〉) and magnetostriction (λs).展开更多
SINCE the discovery of the giant magneto-impedance (GMI) effects in amorphous wire (or rib-bon) of CoFeSiB and nanocrystalline wire (or film) of FeCuNbSiB, it has attracted greatattention due to its promising potentia...SINCE the discovery of the giant magneto-impedance (GMI) effects in amorphous wire (or rib-bon) of CoFeSiB and nanocrystalline wire (or film) of FeCuNbSiB, it has attracted greatattention due to its promising potential applications in industry. Amorphous (and nanocrys-talline) soft magnetic alloys have very large magnetic permeability, when an ac driving currentand an external magnetic field (EMF) are applied, the EMF will damp the magnetic fluxchange caused by the ac driving current, thus the magnetic permeability will decrease; as a re-展开更多
The soft magnetic properties and giant magnetoimpedance(GMI) effect of the multilayered structure(F/SiO2)3/Ag/(SiO2/F)3(F≡Fe71.5Cu1Cr2.5V4Si12B9) films,which were prepared by radio frequency sputtering without and wi...The soft magnetic properties and giant magnetoimpedance(GMI) effect of the multilayered structure(F/SiO2)3/Ag/(SiO2/F)3(F≡Fe71.5Cu1Cr2.5V4Si12B9) films,which were prepared by radio frequency sputtering without and with a longitudinal magnetic field of about 72 kA/m,are studied.The results show that the GMI effect almost cannot be detected in the samples deposited without field,whereas,a longitudinal magnetic field applied during deposition process obviously optimizes the soft magnetic properties of the films,and noticeable GMI effect is obtained.The maximum values of the longitudinal and transverse GMI ratios are 45% and 44% at the frequency of 6.81 MHz,respectively.In addition,the dependence of magnetoimpedance ratio,magnetoresistance ratio,magnetoreactance ratio and effective permeability ratio on the frequency has been investigated.We found that the GMI spectrum curves in the longitudinal and transverse cases almost overlap for the field-deposited sample.The GMI effect is mainly a giant magnetoinductive effect at low frequencies.When f >9 MHz,magnetoreactance ratio changes to a negative,i.e.,the property of reactance changes from inductive to capacitive.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 11604242)Tianjin Research Program of Application Foundation and Advanced Technology, China (No. 14JCQNJC04000)
文摘Influence of composition and annealing temperature on structure and magnetic properties of amorphous and nanocrystalline Fe78.4-xCoxSi9B9Nb2.6Cu1 (x=27.4, 40.0, 51.0, 78.4) alloys was investigated by X-ray diffraction (XRD) and the temperature dependence of permeability. According to the initial crystallization temperature (Tx1) from differential scanning calorimetry (DSC) curves of as-quenched amorphous alloys, 490-700 ℃ isothermal annealing was carded out to obtain the characteristic nanocrystalline structure. Furthermore, the soft magnetic properties were measured by temperature evolution of magnetic permeability to obtain the correlation between Co content, annealing temperature and magnetic permeability. The results show that, on the one hand, the annealing temperature exerts a significant effect on phase structure and initial permeability (μi). The higher-temperature (from 550 to 610 ℃) annealed Co content nanocrystalline samples can remain higher μi at elevated temperature. On the other hand, partial substitution Fe by Co can improve the high-temperature magnetic stability;however, the room-temperature permeability of higher Co content alloys decreases obviously at the same time. This phenomenon was analyzed from the viewpoint of the saturation magnetic induction (Bs), magnetic anisotropy (〈K〉) and magnetostriction (λs).
文摘SINCE the discovery of the giant magneto-impedance (GMI) effects in amorphous wire (or rib-bon) of CoFeSiB and nanocrystalline wire (or film) of FeCuNbSiB, it has attracted greatattention due to its promising potential applications in industry. Amorphous (and nanocrys-talline) soft magnetic alloys have very large magnetic permeability, when an ac driving currentand an external magnetic field (EMF) are applied, the EMF will damp the magnetic fluxchange caused by the ac driving current, thus the magnetic permeability will decrease; as a re-
基金supported by the Science and Technology Key Project of Zhejiang Province,China (Grant No.2006C21085)the Xinmiao Project of Zhejiang Province,China (Grant No.2007R40G2170041)
文摘The soft magnetic properties and giant magnetoimpedance(GMI) effect of the multilayered structure(F/SiO2)3/Ag/(SiO2/F)3(F≡Fe71.5Cu1Cr2.5V4Si12B9) films,which were prepared by radio frequency sputtering without and with a longitudinal magnetic field of about 72 kA/m,are studied.The results show that the GMI effect almost cannot be detected in the samples deposited without field,whereas,a longitudinal magnetic field applied during deposition process obviously optimizes the soft magnetic properties of the films,and noticeable GMI effect is obtained.The maximum values of the longitudinal and transverse GMI ratios are 45% and 44% at the frequency of 6.81 MHz,respectively.In addition,the dependence of magnetoimpedance ratio,magnetoresistance ratio,magnetoreactance ratio and effective permeability ratio on the frequency has been investigated.We found that the GMI spectrum curves in the longitudinal and transverse cases almost overlap for the field-deposited sample.The GMI effect is mainly a giant magnetoinductive effect at low frequencies.When f >9 MHz,magnetoreactance ratio changes to a negative,i.e.,the property of reactance changes from inductive to capacitive.
基金Supported by National Natural Science Foundation of China(50271047)The Natural Science Foundation ofTianjin,as well as the"985"Program Foundation of Tianjin University(003601811)