Topic
Ferromagnetism
About: Ferromagnetism is a research topic. Over the lifetime, 55095 publications have been published within this topic receiving 1211590 citations.
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TL;DR: In this paper, the anomalous Hall effect is observed in ZnO:Co thin films and the presence of a side-jump contribution further supports an intrinsic origin for ferromagnetism.
Abstract: Diluted magnetic semiconducting ZnO:Co thin films with above room-temperature TC were prepared. Transmission electron microscopy and x-ray diffraction studies indicate the ZnO:Co thin films are free of secondary phases. The magnetization of the ZnO:Co thin films shows a free electron carrier concentration dependence, which increases dramatically when the free electron carrier concentration exceeds ∼1019 cm−3, indicating a carrier-mediated mechanism for ferromagnetism. The anomalous Hall effect is observed in the ZnO:Co thin films. The anomalous Hall coefficient and its dependence on longitudinal resistivity were analyzed. The presence of a side-jump contribution further supports an intrinsic origin for ferromagnetism in ZnO:Co thin films. These observations together with the magnetic anisotropy and magnetoresistance results support an intrinsic carrier-mediated mechanism for ferromagnetic exchange in ZnO:Co diluted magnetic semiconductor materials.
29 citations
TL;DR: In this article, a room temperature ferromagnetic Zn0.95Co0.05O thin film with (002) preferential orientation has been deposited by pulsed laser deposition at different substrate temperatures on n-type (100) silicon substrate.
Abstract: Room temperature ferromagnetic Zn0.95Co0.05O thin film with (002) preferential orientation has been deposited by pulsed laser deposition at different substrate temperatures on n-type (100) silicon substrate. A maximum saturation magnetization of 0.86μB∕Co was achieved at room temperature. High-resolution transmission electron microscope and x-ray photoelectron spectroscopy results indicate that this ferromagnetism behavior is not due to Co microclusters in the thin film. Zinc interstitials, oxygen vacancies, and lattice defects induced by low substrate deposition temperature show a significant effect on ferromagnetic behavior. By changing the substrate deposition temperature to control the amount of zinc interstitials, oxygen vacancies, and lattice defects, ferromagnetism can be tuned significantly as well, which is a direct evidence that these defects contributed to the ferromagnetism in ZnO:Co thin films.
29 citations
TL;DR: In this paper, a modification of magnetic anisotropy in the MgO/CoFeB/Pd and MgE/CoEb/Pt systems, using electric fields of order 500?MV?m?1 (0.5?V?nm?1) applied across a thermally grown SiO2 as a gate dielectric.
Abstract: Data are presented which indicate a modification of magnetic anisotropy in the MgO/CoFeB/Pd and MgO/CoFeB/Pt systems, using electric fields of order 500?MV?m?1 (0.5?V?nm?1) applied across a thermally grown SiO2 as a gate dielectric. The effect is most prominent at low temperature (12?K) and is manifested as a small change in coercivity. The sign of the effect depends on the choice of both capping layer and annealing temperature. The results suggest that both interfaces play a role in the appearance of perpendicular magnetic anisotropy in these thin-film stacks, and not just the interface with MgO.
29 citations
TL;DR: In this article, the magnetic and microstructural properties of sintered magnet doped with Dy2O3 and DyHx powders were studied, and it was shown that the coercivity of the dyHx-doped magnet improved, with no change in the remanence.
Abstract: The magnetic and microstructural properties of (Nd27.68Dy4.89)-Febal.B1.0M2.4 (wt. %, M = Cu, Al, Co, and Nb) sintered magnets doped with Dy2O3 and DyHx powders were studied. The coercivity of the DyHx-doped magnet improved, with no change in the remanence. Well-developed core-shell microstructures were seen in the DyHx-doped magnet, as compared to the case of the Dy2O3-doped magnet. Diffusion of Dy was enhanced in the DyHx-doped magnet, probably because dissolution of hydrogen in Nd2Fe14B increased the lattice parameter. The (00L) grain alignment in the DyHx-doped magnet was also improved.
29 citations
TL;DR: In this paper, the thermoelectricity of UCoGe has been investigated and it has been shown that under magnetic field applied along the $b$ axis, a sharp peak is observed in the thermopower at ${H}^{*}=11.1$ T and low temperature that becomes broader at higher temperatures.
Abstract: UCoGe exhibits superconductivity in the presence of ferromagnetism. When a field is applied along the $b$ axis (perpendicular to the easy axis), ferromagnetism is weakened, and superconductivity is enhanced. This enhancement has been attributed to an increase in coupling as observed in the enhanced effective mass produced by the critical fluctuations as the ferromagnetic transition is strongly suppressed. However, it is also important to know if and how the Fermi surface changes near the critical point. Here we report measurements of the thermoelectricity of UCoGe that reveal a low-carrier-density metal. Under magnetic field applied along the $b$ axis, a sharp peak is observed in the thermopower of UCoGe at ${H}^{*}=11.1$ T and low temperature that becomes broader at higher temperatures. At higher field, the thermopower changes sign, which suggests a modification of the Fermi surface. We analyze these results using a topological change in the Fermi surface and show that this can explain both the thermopower and the enhanced superconductivity.
29 citations