Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and or...Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.展开更多
We have reported new magnetic and optical properties of Mn2O3 nanostructures. The nanostructures have been synthesized by the hydrothermal method combined with the adjustment of pH values in the reaction system. The p...We have reported new magnetic and optical properties of Mn2O3 nanostructures. The nanostructures have been synthesized by the hydrothermal method combined with the adjustment of pH values in the reaction system. The particular characteristics of the nanostructures have been analyzed by employing X-Ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray （EDX） analysis, transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM）, Raman spectroscopy （RS）, UV-visible spectroscopy, and the vibrating sample magnetometer （VSM）. Structural investigation manifests that the synthesized Mn2O3 nanostructures are orthorhombic crystal. Magnetic investigation indicates that the Mn2O3 nanostructures are antiferromagnetic and the antiferromagnetic transition temperature is at TN = 83 K. Furthermore, the Mn2O3 nanostructures possess canted antiferromagnetic order below the Neel temperature due to spin frustration, resulting in hysteresis with large coercivity （1580 Oe） and remnant magnetization （1.52 emu/g）. The UV-visible spectrophotometry was used to determine the transmittance behaviour of Mn203 nanostructures. A direct optical band gap of 1.2 eV was acquired by using the Davis-Mott model. The UV-visible spectrum indicates that the absorption is prominent in the visible region, and transparency is more than 80% in the UV region.展开更多
We report the first nuclear magnetic resonance （NMR） study on single crystals of staircase Kagome antiferromagnet PbCu3Te07 （TN1 -36K）. A Curie constant θ -140K is obtained by a Curie Weiss fit to the high- tempe...We report the first nuclear magnetic resonance （NMR） study on single crystals of staircase Kagome antiferromagnet PbCu3Te07 （TN1 -36K）. A Curie constant θ -140K is obtained by a Curie Weiss fit to the high- temperature Knight shift of 125 Te. The hyperfine coupling constant is estimated to be 125Ahf = -67 kOe/#B, and a strong interlayer coupling among staircase Kagome planes is suggested with such a large hyperfine coupling, according to the lattice structure. The 63,65Cu NMR spectra are found by the zero-field （ZF） NMR at T = 2 K, and the internal hyperfine fields are estimated to be 10.3 T and 9.6 T, for Cu（1） and Cu（2） sites, respectively, in the lattice. A second type of ZF NMFt signal with a large rf enhancement is also seen after field-cycling through a high magnetic field.展开更多
基金Supported by the Youth Science Foundation of Shanxi Province under Grant No 2013021010-3the National Natural Science Foundation of China under Grant Nos 61434002 and 11404202
文摘Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.
基金Project supported by the Fundamental Development Fund and Chancellor Scholarship Program,China (Grant No.YJ2010-014)the Fundamental Research Funds for the Central Universities of China (Grant No. FRF-BR-09-007A)
文摘We have reported new magnetic and optical properties of Mn2O3 nanostructures. The nanostructures have been synthesized by the hydrothermal method combined with the adjustment of pH values in the reaction system. The particular characteristics of the nanostructures have been analyzed by employing X-Ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray （EDX） analysis, transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM）, Raman spectroscopy （RS）, UV-visible spectroscopy, and the vibrating sample magnetometer （VSM）. Structural investigation manifests that the synthesized Mn2O3 nanostructures are orthorhombic crystal. Magnetic investigation indicates that the Mn2O3 nanostructures are antiferromagnetic and the antiferromagnetic transition temperature is at TN = 83 K. Furthermore, the Mn2O3 nanostructures possess canted antiferromagnetic order below the Neel temperature due to spin frustration, resulting in hysteresis with large coercivity （1580 Oe） and remnant magnetization （1.52 emu/g）. The UV-visible spectrophotometry was used to determine the transmittance behaviour of Mn203 nanostructures. A direct optical band gap of 1.2 eV was acquired by using the Davis-Mott model. The UV-visible spectrum indicates that the absorption is prominent in the visible region, and transparency is more than 80% in the UV region.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374364 and 11222433the National Basic Research Program of China under Grant No 2011CBA00112the Scientific Research Foundation for the Returned Overseas Chinese Scholars of State Education Ministry
文摘We report the first nuclear magnetic resonance （NMR） study on single crystals of staircase Kagome antiferromagnet PbCu3Te07 （TN1 -36K）. A Curie constant θ -140K is obtained by a Curie Weiss fit to the high- temperature Knight shift of 125 Te. The hyperfine coupling constant is estimated to be 125Ahf = -67 kOe/#B, and a strong interlayer coupling among staircase Kagome planes is suggested with such a large hyperfine coupling, according to the lattice structure. The 63,65Cu NMR spectra are found by the zero-field （ZF） NMR at T = 2 K, and the internal hyperfine fields are estimated to be 10.3 T and 9.6 T, for Cu（1） and Cu（2） sites, respectively, in the lattice. A second type of ZF NMFt signal with a large rf enhancement is also seen after field-cycling through a high magnetic field.
