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• The nanoscale structural heterogeneity and magnetic properties were analyzed by atomic force microscopy and Mössbauer spectroscopy. • The nanoscale structural heterogeneity of Fe 80 Si 9 B 11 amorphous alloy attenuates monotonically with a decrease in cooling rate. • The annihilation of flow units induces the enhancement in ferromagnetic exchange interaction and weakening of magnetic anisotropy. • The ameliorated magnetic properties with decreasing cooling rate can be attributed to the degeneration of nanoscale structural heterogeneity. Despite that the nanoscale structural heterogeneity of amorphous alloys has been confirmed by advanced experimental observations and theoretical simulations, the underlying link between the structural heterogeneity and magnetic properties remains poorly known. In this work, the effect of cooling rate on the nanoscale structural heterogeneity and magnetic properties of Fe 80 Si 9 B 11 amorphous ribbons (Fe-Si-BAR) was studied by atomic force microscopy and Mössbauer spectroscopy. The results show that the degeneration of nanoscale structural heterogeneity substantially induces an improvement in soft magnetic properties with decreasing cooling rate. Specifically, the volume fraction of flow units reduces significantly with the decrease of cooling rate, and some of the flow units annihilate and transform to the ideal elastic matrix. The structural densification and reduction of the number density of quasidislocation dipole result in an enhancement in ferromagnetic exchange interaction and weakening of magnetic anisotropy. Therefore, the saturation magnetic flux density increases and coercivity decreases with reducing cooling rate. Our results provide new insight into understanding the structural mechanism in the ameliorated magnetic properties of Fe-based amorphous alloys with decreasing cooling rate. [ABSTRACT FROM AUTHOR]

Abstract: The film of La2/3Ca1/3MnO3 (LCMO), YBa2Cu3O7−δ (YBCO) and YBCO/LCMO bi-layer were prepared by rf off-axis magnetic sputtering technique on SrTiO3 (STO) substrate. The structures, including the surface and interfacial morphology, the interfacial diffusion and so on, have been characterized by X-ray diffraction (XRD), auger electronic energy spectroscopy (AES) and atomic force microscopy (AFM). Through a 50–200eV energy range, a single layer of YBCO shows a very small reflectance (<2%), while a single layer of LCMO shows a higher reflectance of about 25% at the energy of about 75eV, which is much higher than that of metal W. Even higher reflectance (>50%) at about 75eV has been observed in the LCMO/YBCO bi-layers. [Copyright &y& Elsevier]

• Crystallization kinetics of FeNiPC(Nb) amorphous alloys was investigated. • Both thermal stability and activation energy increase after addition 1% Nb. • The magnitude of local Avrami exponent is altered with Nb addition. • The growth rate of primary crystallized phase is restrained with Nb addition. The effects of minor Nb addition on the crystallization mechanism for a FeNiPC(Nb) amorphous alloy were studied via investigating its non-isothermal crystallization kinetics. With minor Nb addition, the thermal stability of the alloy increases as evidenced by the enlargement of the supercooled liquid region. Meanwhile, the location activation energy of both Nb-added and without Nb-added alloys correlates positively with the crystallized volume fraction during the whole primary crystallization stages, as calculated by the isoconversional methods. However, the kinetics analysis using the modified Johnson-Mehl-Avrami-Kolmogorov equation indicates that the addition of Nb changes the crystallization mode of the alloys, that is, from the growth with a decrease nucleation rate to a constant nucleation rate in a diffusion-controlled manner. This can be further confirmed by the atomic force microscopy showing that Nb would restrain the atomic diffusivity and suppress the crystallization growth rate in this alloy. [ABSTRACT FROM AUTHOR]

• The nanoscale structural heterogeneity was analyzed by small-angle X-ray scattering and atomic force microscopy. • The microalloying of Co and Ni exhibits an opposite effect on the nanoscale structural heterogeneity. • The variation of mechanical behavior further proves the evolution of the nanoscale structural heterogeneity with Co and Ni substitution. • The evolution of magnetic properties induced by microalloying can be attributed to the variation of nanoscale structural heterogeneity. Nanoscale structural heterogeneity is a critical parameter for understanding the structure-property relationships in amorphous alloys. Herein, the small-angle X-ray scattering and atomic force microscopy were utilized to quantitatively investigate the nanoscale structural heterogeneity of the Fe 80- x M x Si 9 B 11 (M = Co and Ni; x = 0, 2, 4) amorphous alloys. The results show that the nanoscale structural heterogeneity of the amorphous alloys increases prominently with Ni substitution, but gradually decreases with the increase of Co content. Such evolution of structural heterogeneity was further verified by the changes in mechanical behavior. The microalloying of Ni can increase the plastic deformation ability and reduce the microhardness, whereas an opposite effect is found in the Co-doped alloys. Finally, Mössbauer spectroscopy reveals an enhancement in ferromagnetic exchange interaction and magnetic anisotropy with Co substitution, while the microalloying of Ni leads to a deteriorative result. Such variations in magnetic properties can be attributed to the evolution of nanoscale structural heterogeneity with Co and Ni additions. Our observation serves as a link between the nanoscale structural heterogeneity and magnetic properties, providing a new sight into understanding the structural origin of the changes in magnetic properties of Fe-based amorphous alloys. [ABSTRACT FROM AUTHOR]

• The relaxation-induced evolution of nanoscale structural heterogeneity is analyzed by atomic force microscopy in Fe 80 Si 9 B 11 metallic glass. • The degeneration of nanoscale structural heterogeneity induces the improvement of soft magnetic properties. • The soft magnetic properties can be optimized by selectively tailoring the intrinsic structural heterogeneity of Fe-based metallic glass. Despite the mesoscopic isotropic nature of metallic glasses, there is a certain degree of structural heterogeneity down to the nanoscale. However, how structural heterogeneity affects the magnetic properties is still unclear. In this work, the relaxation-induced structural heterogeneity and magnetic properties evolution of Fe 80 Si 9 B 11 metallic glass were investigated by atomic force microscopy (AFM) and Mössbauer spectroscopy. We revealed that the correlation-length of nanoscale heterogeneity relates closely with the ferromagnetic exchange interaction together with the magnetic anisotropy, providing experimental evidence of the intrinsic link between the nanoscale structural heterogeneity and magnetic properties for Fe-based metallic glasses. The degeneration of nanoscale structural heterogeneity induces the enhancement of the ferromagnetic exchange interaction and weakening of the magnetic anisotropy. Our results have a vital significance in understanding the structure-property relationship of metallic glass. [ABSTRACT FROM AUTHOR]