Zero field cooled (ZFC) and field cooled (FC) DC magnetization and AC susceptibility of sintered SrRuO 3 were measured over the magnetic ordering temperature. The peak in susceptibility against temperature shifts ...Zero field cooled (ZFC) and field cooled (FC) DC magnetization and AC susceptibility of sintered SrRuO 3 were measured over the magnetic ordering temperature. The peak in susceptibility against temperature shifts to lower temperature when the bias field increases. As the field still increases, the peak breaks into two peaks. One peak still shifts to lower temperature; the other shifts to higher temperature. Zero bias field susceptibility was measured at different frequencies. The peak value decreases as the increase of frequency, but it does not shift to higher temperature as reported previously. The results show that SrRuO 3 is not spin glass, but ferromagnet.展开更多
The magnetic property in a material is induced by the unpaired electrons. This can occur due to defect states which can enhance the magnetic moment and the spin polarization. In this report, CdS and CdTe thin films ar...The magnetic property in a material is induced by the unpaired electrons. This can occur due to defect states which can enhance the magnetic moment and the spin polarization. In this report, CdS and CdTe thin films are grown on FTO glass substrates by chemical bath deposition and close-spaced sublimation, respectively. The magnetic properties, which are introduced from oxygen states, are found in CdS and CdTe thin films. From the hysteresis loop of magnetic moment it is revealed that CdS and CdTe thin films have different kinds of magnetic moments at different temperatures. The M–H curves indicate that from 100 K to 350 K, CdS and CdTe thin films show paramagnetism and diamagnetism, respectively.A superparamagnetic or a weakly ferromagnetic response is found at 5 K. It is also observed from ZFC/FC curves that magnetic moments decrease with temperature increasing. Spin polarized density functional calculation for spin magnetic moment is also carried out.展开更多
Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precurso...Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.展开更多
文摘Zero field cooled (ZFC) and field cooled (FC) DC magnetization and AC susceptibility of sintered SrRuO 3 were measured over the magnetic ordering temperature. The peak in susceptibility against temperature shifts to lower temperature when the bias field increases. As the field still increases, the peak breaks into two peaks. One peak still shifts to lower temperature; the other shifts to higher temperature. Zero bias field susceptibility was measured at different frequencies. The peak value decreases as the increase of frequency, but it does not shift to higher temperature as reported previously. The results show that SrRuO 3 is not spin glass, but ferromagnet.
基金supported by the National Natural Science Foundation of China(Grant No.61474103)the Chinese Scholarship Council(CSC)Fellowship for H.Tariq Masood and Z.Muhammad
文摘The magnetic property in a material is induced by the unpaired electrons. This can occur due to defect states which can enhance the magnetic moment and the spin polarization. In this report, CdS and CdTe thin films are grown on FTO glass substrates by chemical bath deposition and close-spaced sublimation, respectively. The magnetic properties, which are introduced from oxygen states, are found in CdS and CdTe thin films. From the hysteresis loop of magnetic moment it is revealed that CdS and CdTe thin films have different kinds of magnetic moments at different temperatures. The M–H curves indicate that from 100 K to 350 K, CdS and CdTe thin films show paramagnetism and diamagnetism, respectively.A superparamagnetic or a weakly ferromagnetic response is found at 5 K. It is also observed from ZFC/FC curves that magnetic moments decrease with temperature increasing. Spin polarized density functional calculation for spin magnetic moment is also carried out.
文摘Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.
