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The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe1.908Ni0.092As2 single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10–4) was observed in the direction of twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe1.908Ni0.092As2 can be well explained by a flux-pinning-induced mechanism. [ABSTRACT FROM AUTHOR]

A chiral soliton lattice (CSL) is a topological spin-texture that has potential applications in next-generation spintronic devices. In this work, we performed angle-dependence of magnetization and electron spin resonance (ESR) investigations on the CSL host Yb(Ni1−xCux)3Al9 with x = 0.06 (YNCA). The angle-dependent magnetization reveals a peculiar variable magnetic anisotropy. The maximum magnetization axis is parallel to the ab-plane below the field of ∼35.7 kOe while shifts to the c-axis at higher fields. The microwave responses of the CSL helicoid and ferromagnetic resonance (FMR) of the forced ferromagnetic state (FFM) are observed and appear as two resonance lines on ESR spectra with the highest intensities in the ab-plane. When the external field is rotated from H ⊥ c to H / / c , the resonance field H r 1 corresponding to the CSL helicoid decreases while H r 2 correlated with the FMR increases. Furthermore, the temperature-dependent ESR shows that the CSL persists until 15 K much higher than TC (6.4 K), which suggests a precursor phenomenon. The microwave response in YNCA provides a powerful tool for modulating and researching the CSL. [ABSTRACT FROM AUTHOR]

Co3Sn2S2, a quasi-two-dimensional system with a kagome lattice, has been found to be a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co3Sn2S2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient Ku up to 8.3 × 105 J m−3, which indicates that it is extremely difficult to align the small moment of 0.29 μB/Co on the kagome lattice from the c axis to the ab plane. The out-of-plane angular dependence of Hall conductivity further reveals strong anisotropies in the Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For the in-plane situation, the longitudinal and transverse measurements for both I // a and I ⊥ a cases show that the transport on the kagome lattice is isotropic. These results provide the essential understanding of the magnetization and transport behaviors for the magnetic Weyl semimetal, Co3Sn2S2. [ABSTRACT FROM AUTHOR]

One method of calculating critical exponents based on the field dependence on magnetic entropy change was applied to study critical behavior in Pr0.55Sr0.45MnO3. By using the obtained critical exponents, the modified Arrott plot [A. Arrott and J. E. Noakes, Phys. Rev. Lett. 19, 786 (1967)] is consistent with that by using conventional method. The calculated critical exponents not only obey the scaling theory, but also inosculate the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, Phys. Rev. 136, A1626 (1964)]. It eliminates the drawback due to utilization of multistep nonlinear fitting in a conventional manner. Therefore, this means can be applied to investigate critical behavior. [ABSTRACT FROM AUTHOR]

We have studied the magnetotransport properties of the La[sub l.4]Sr[sub l.6-y]Ba[sub y]Mn[sub 2]O[sub 7] (y≤0.50) samples with a bilayered perovskite structure. For lightly doped samples, the metal-insulator transition accompanying a three-dimensional ferromagnetic transition can be understood commonly in terms of the double-exchange interaction. For heavier doped samples, the metal-insulator transition remains without a ferromagnetic transition and shifts to higher temperature with increasing Ba doping level. On account of the coexistence of short-range ferromagnetic ordering and paramagnetic state, the results can be explained by a recent percolation model based on phase separation. The percolative metal-insulator transition is consistent with the relative ferromagnetic metallic fraction change with temperature and doping level. [ABSTRACT FROM AUTHOR]

The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe1.908Ni0.092As2 single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10–4) was observed in the direction of twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe1.908Ni0.092As2 can be well explained by a flux-pinning-induced mechanism. [ABSTRACT FROM AUTHOR]

We have studied the magnetic and magnetotransport properties of the perovskite LaMn[sub 1-x]Cu[sub x]O[sub 3] (x≤0.3). All of these compounds show ferromagnetism and cluster glass behavior at low temperatures. Though no metallic-insulating transition associated with the ferromagnetic-paramagnetic transition appears, a large magnetoresistance was observed in the ferromagnetic phase. Due to the fact that the Cu ion in these compounds is divalent, the ferromagnetism in LaMn[sub 1-x]Cu[sub x]O[sub 3] is believed to be consistent with the Mn[sup 3+]-O-Mn[sup 4+] double-exchange mechanism. These results suggest that double exchange and large magnetoresistance can be obtained by direct Mn-site doping. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A chiral soliton lattice (CSL) is a topological spin-texture that has potential applications in next-generation spintronic devices. In this work, we performed angle-dependence of magnetization and electron spin resonance (ESR) investigations on the CSL host Yb(Ni1−xCux)3Al9 with x = 0.06 (YNCA). The angle-dependent magnetization reveals a peculiar variable magnetic anisotropy. The maximum magnetization axis is parallel to the ab-plane below the field of ∼35.7 kOe while shifts to the c-axis at higher fields. The microwave responses of the CSL helicoid and ferromagnetic resonance (FMR) of the forced ferromagnetic state (FFM) are observed and appear as two resonance lines on ESR spectra with the highest intensities in the ab-plane. When the external field is rotated from H ⊥ c to H / / c , the resonance field H r 1 corresponding to the CSL helicoid decreases while H r 2 correlated with the FMR increases. Furthermore, the temperature-dependent ESR shows that the CSL persists until 15 K much higher than TC (6.4 K), which suggests a precursor phenomenon. The microwave response in YNCA provides a powerful tool for modulating and researching the CSL. [ABSTRACT FROM AUTHOR]

Co3Sn2S2, a quasi-two-dimensional system with a kagome lattice, has been found to be a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co3Sn2S2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient Ku up to 8.3 × 105 J m−3, which indicates that it is extremely difficult to align the small moment of 0.29 μB/Co on the kagome lattice from the c axis to the ab plane. The out-of-plane angular dependence of Hall conductivity further reveals strong anisotropies in the Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For the in-plane situation, the longitudinal and transverse measurements for both I // a and I ⊥ a cases show that the transport on the kagome lattice is isotropic. These results provide the essential understanding of the magnetization and transport behaviors for the magnetic Weyl semimetal, Co3Sn2S2. [ABSTRACT FROM AUTHOR]