BaFe10A12O19/poly（m-toluidine） （BFA/PMT） composites were synthesized by in-situ polymerization of m-toluidine in the presence of BaFe10Al2O19 particles. The structure, composition and morphology of the obtained sa...BaFe10A12O19/poly（m-toluidine） （BFA/PMT） composites were synthesized by in-situ polymerization of m-toluidine in the presence of BaFe10Al2O19 particles. The structure, composition and morphology of the obtained samples were characterized by using XRD, FT-IR, UV-visible spectroscopy, SEM and TEM techniques. Their electrical conductivity, magnetic property and microwave absorbing property were measured by the four-probe meter, the vibrating sample magnetometer and the vector network analyzer, respectively. The results indicated that BFA particles were coated effectively by PMT polymer and some interactions between PMT and BFA particles existing in the composites. The conductivity of BFA/PMT composite is smaller than that of pure polymers and its saturation magnetization is a little smaller than that of pure BFA. The influence of the constitution and film thickness of absorbent on its microwave absorbing property is evident. The microwave absorbing properties of the BFA/PMT composites are better than those of pure BFA and PMT. When optimizing the mass rate of BFA/PMT to 0.3, the absorbent with 2 mm film thickness has the minimum reflection loss of -28.26 dB at approximate 14.24 GHz, and the maximum available bandwidth of 8.8 GHz, respectively. The results show that these composites can be used as advancing absorption and shielding materials due to their favorable microwave absorbing property.展开更多
Exchange bias between ferromagnetic and antiferromagnetic layers has been widely utilized in spintronic devices.Controlling the exchange bias in magnetic multilayers by an electric field(E-field)has been proposed as a...Exchange bias between ferromagnetic and antiferromagnetic layers has been widely utilized in spintronic devices.Controlling the exchange bias in magnetic multilayers by an electric field(E-field)has been proposed as a low-power solution for manipulating the macroscopic properties such as exchange bias fields and magnetization values,while how the magnetic domains respond to the E-fields has rarely been reported in an exchange-biased system.Here,we realize the vector imaging of reversible electrical modulation of magnetization reversal in exchange-biased CoFeB/IrMn/PMN-PT(011)multiferroic heterostructures,utilizing in-situ quantitative magneto-optical Kerr effect(MOKE)microscopy.Under the electrical control,magnetic domains at-80 Oe rotate reversibly between around 160°and 80°-120°,whose transverse components reverse from 225°to 45°correspondingly.Moreover,pixel-by-pixel comparisons are conducted to further imply the reversible magnetization reversal by E-fields.Efield-induced reversible magnetization reversal is also demonstrated without applying external magnetic fields.Vector imaging of electrical manipulation of exchange bias is of great significance in understanding the magnetoelectric effect and the development of next-generation spintronic devices.展开更多
基金supported by the National Nature Science Foundation of China (21071125)the Natural Science Foundation of Zhejiang Province(Y4100022,Y4090636)the Science and Technology Key Project of Zhejiang Province (2010C11053)
文摘BaFe10A12O19/poly（m-toluidine） （BFA/PMT） composites were synthesized by in-situ polymerization of m-toluidine in the presence of BaFe10Al2O19 particles. The structure, composition and morphology of the obtained samples were characterized by using XRD, FT-IR, UV-visible spectroscopy, SEM and TEM techniques. Their electrical conductivity, magnetic property and microwave absorbing property were measured by the four-probe meter, the vibrating sample magnetometer and the vector network analyzer, respectively. The results indicated that BFA particles were coated effectively by PMT polymer and some interactions between PMT and BFA particles existing in the composites. The conductivity of BFA/PMT composite is smaller than that of pure polymers and its saturation magnetization is a little smaller than that of pure BFA. The influence of the constitution and film thickness of absorbent on its microwave absorbing property is evident. The microwave absorbing properties of the BFA/PMT composites are better than those of pure BFA and PMT. When optimizing the mass rate of BFA/PMT to 0.3, the absorbent with 2 mm film thickness has the minimum reflection loss of -28.26 dB at approximate 14.24 GHz, and the maximum available bandwidth of 8.8 GHz, respectively. The results show that these composites can be used as advancing absorption and shielding materials due to their favorable microwave absorbing property.
基金supported by the National Key R&D Program of China(2018YFB0407601)the National Natural Science Foundation of China(91964109,62071374 and 51802248)the National 111 Project of China(B14040).
文摘Exchange bias between ferromagnetic and antiferromagnetic layers has been widely utilized in spintronic devices.Controlling the exchange bias in magnetic multilayers by an electric field(E-field)has been proposed as a low-power solution for manipulating the macroscopic properties such as exchange bias fields and magnetization values,while how the magnetic domains respond to the E-fields has rarely been reported in an exchange-biased system.Here,we realize the vector imaging of reversible electrical modulation of magnetization reversal in exchange-biased CoFeB/IrMn/PMN-PT(011)multiferroic heterostructures,utilizing in-situ quantitative magneto-optical Kerr effect(MOKE)microscopy.Under the electrical control,magnetic domains at-80 Oe rotate reversibly between around 160°and 80°-120°,whose transverse components reverse from 225°to 45°correspondingly.Moreover,pixel-by-pixel comparisons are conducted to further imply the reversible magnetization reversal by E-fields.Efield-induced reversible magnetization reversal is also demonstrated without applying external magnetic fields.Vector imaging of electrical manipulation of exchange bias is of great significance in understanding the magnetoelectric effect and the development of next-generation spintronic devices.
