Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness...Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness,wepresent a theory on the electronic transport in magnetic film,in which the average autocorrelation function (ACF) forsurface roughness is described by a Gaussion model.Our result shows that the conductivity is a sensitive function ofsurface roughness and exchange energy.It is also found that in the thin film limit and in the lower-order approximationof the surface scattering,the total conductivity is given by a sum of conductivities of all the subbands and the two spinchannels,for each subband and each spin channel the scattering rates due to the impurities and two surfaces are additive.展开更多
The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green＇s function technique. It is found that four energy gaps and corresp...The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green＇s function technique. It is found that four energy gaps and corresponding four frequencie in middle of energy gaps exist in the magnon band along Kx direction perpendicular to the superlattice plane. The spin quantum numbers and the interlayer exchange couplings all affect the four frequencies in middle of the energy gaps. When all interlayer exchange couplings are same, the effect of spin quantum numbers on the frequency wg1 in middle of the energy gap Δw12 is complicated, and the frequency wg1 depends on the match of spin quantum numbers in each layer. Meanwhile, the frequencies wg2, wg3, and wg4 in middle of other energy gaps increase monotonously with increasing spin quantum numbers. When the spin quantum numbers in each layer are same, the frequencies wg1, wg2, wg3, and wg4 all increase monotonously with increasing interlayer exchange couplings.展开更多
The compound {[Cu(Hpht)(N_3)]·H_2O}_n (Hpht = hydrogen phthalate) is formedby chains of copper atoms bridged simultaneously by syn-syn carboxylato and end-on azido bridges.Taking into account the large Cu-O(1)-C(...The compound {[Cu(Hpht)(N_3)]·H_2O}_n (Hpht = hydrogen phthalate) is formedby chains of copper atoms bridged simultaneously by syn-syn carboxylato and end-on azido bridges.Taking into account the large Cu-O(1)-C(7) bond angle of the single carboxylato bridge (131°), orthe large Cu-N(11)-Cu bond angle of the azido bridge (111.9°), a moderately intrachainantiferromagnetic behavior should be expected for the compound. This paper is devoted to examiningthe apparently anomalous intrachain ferromagnetic behavior of {[Cu(Hpht)(N_3)]·H_2O}_n, using firstprinciples within the full potential linearized augmented plane wave (FP-LAPW) method. The totalenergy, the density of states (DOS), and the spin distributions are obtained. The atomic spindistribution has been analyzed as resulting from the interplay of electron delocalization and spinpolarization. The DOS reveals a surprisingly strong exchange interaction between the d type orbitalsof the copper and the π molecular orbitals of the two ligands.展开更多
The specific heats of both a two-layer ferromagnetic superlattice and a two-layer ferrimagnetic one arestudied.It is found that the spin quantum numbers,the interlayer and intralayer exchange couplings,the anisotropy,...The specific heats of both a two-layer ferromagnetic superlattice and a two-layer ferrimagnetic one arestudied.It is found that the spin quantum numbers,the interlayer and intralayer exchange couplings,the anisotropy,theapplied magnetic field,and the temperature all affect the specific heat of these superlattices.For both the ferromagneticand ferrimagnetic superlattices,the specific heat decreases with increasing the spin quantum number,the absolutevalue of interlayer exchange coupling,intralayer exchange coupling,and anisotropy,while it increases with increasingtemperature at low temperatures.When an applied magnetic field is enhanced,the specific heat decreases in the two-layerferromagnetic superlattice,while it is almost unchanged in the two-layer ferrimagnetic superlattice at low fieldrange at low temperatures.展开更多
FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properti...FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properties of [FePt/Ag]10multilayer films are influenced by the Ag content. The highest coercivity is obtained for those multilayer films that the Ag content is about 25%. The analysis for the re- manence curves shows that the lower FePt layer thickness is favorable for decreasing the intergranular interaction. Re- sult of XRD shows that a thick Ag layer can enhance the intensity of FePt(001) peak. A magnetic activation volume of the order of 10?24 m3 is obtained by the measurement of magnetic viscosity, showing that it is promising to be ultra- high density recording media.展开更多
基金the Natural Science Foundation of Education Bureau of Jiangsu Province of China under Grant No.05KJB140008the"333"Project Funds of Jiangsu Province of China
文摘Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness,wepresent a theory on the electronic transport in magnetic film,in which the average autocorrelation function (ACF) forsurface roughness is described by a Gaussion model.Our result shows that the conductivity is a sensitive function ofsurface roughness and exchange energy.It is also found that in the thin film limit and in the lower-order approximationof the surface scattering,the total conductivity is given by a sum of conductivities of all the subbands and the two spinchannels,for each subband and each spin channel the scattering rates due to the impurities and two surfaces are additive.
基金Supported by the Natural Science Foundation of Liaoning Province of China under Grant No. 20062040
文摘The frequency in middle of magnon energy band in a five-layer ferromagnetic superlattice is studied by using the linear spin-wave approach and Green＇s function technique. It is found that four energy gaps and corresponding four frequencie in middle of energy gaps exist in the magnon band along Kx direction perpendicular to the superlattice plane. The spin quantum numbers and the interlayer exchange couplings all affect the four frequencies in middle of the energy gaps. When all interlayer exchange couplings are same, the effect of spin quantum numbers on the frequency wg1 in middle of the energy gap Δw12 is complicated, and the frequency wg1 depends on the match of spin quantum numbers in each layer. Meanwhile, the frequencies wg2, wg3, and wg4 in middle of other energy gaps increase monotonously with increasing spin quantum numbers. When the spin quantum numbers in each layer are same, the frequencies wg1, wg2, wg3, and wg4 all increase monotonously with increasing interlayer exchange couplings.
文摘The compound {[Cu(Hpht)(N_3)]·H_2O}_n (Hpht = hydrogen phthalate) is formedby chains of copper atoms bridged simultaneously by syn-syn carboxylato and end-on azido bridges.Taking into account the large Cu-O(1)-C(7) bond angle of the single carboxylato bridge (131°), orthe large Cu-N(11)-Cu bond angle of the azido bridge (111.9°), a moderately intrachainantiferromagnetic behavior should be expected for the compound. This paper is devoted to examiningthe apparently anomalous intrachain ferromagnetic behavior of {[Cu(Hpht)(N_3)]·H_2O}_n, using firstprinciples within the full potential linearized augmented plane wave (FP-LAPW) method. The totalenergy, the density of states (DOS), and the spin distributions are obtained. The atomic spindistribution has been analyzed as resulting from the interplay of electron delocalization and spinpolarization. The DOS reveals a surprisingly strong exchange interaction between the d type orbitalsof the copper and the π molecular orbitals of the two ligands.
基金Supported by the Natural Science Foundation of Liaoning Province of China under Grant No.20062040
文摘The specific heats of both a two-layer ferromagnetic superlattice and a two-layer ferrimagnetic one arestudied.It is found that the spin quantum numbers,the interlayer and intralayer exchange couplings,the anisotropy,theapplied magnetic field,and the temperature all affect the specific heat of these superlattices.For both the ferromagneticand ferrimagnetic superlattices,the specific heat decreases with increasing the spin quantum number,the absolutevalue of interlayer exchange coupling,intralayer exchange coupling,and anisotropy,while it increases with increasingtemperature at low temperatures.When an applied magnetic field is enhanced,the specific heat decreases in the two-layerferromagnetic superlattice,while it is almost unchanged in the two-layer ferrimagnetic superlattice at low fieldrange at low temperatures.
文摘FePt/Ag]10 multilayers were deposited on glass substrates by magnetron sputtering. After being annealed at 550℃ for 30 min, the coercivities of [FePt/Ag]10 multilayer films were observably improved. Magnetic properties of [FePt/Ag]10multilayer films are influenced by the Ag content. The highest coercivity is obtained for those multilayer films that the Ag content is about 25%. The analysis for the re- manence curves shows that the lower FePt layer thickness is favorable for decreasing the intergranular interaction. Re- sult of XRD shows that a thick Ag layer can enhance the intensity of FePt(001) peak. A magnetic activation volume of the order of 10?24 m3 is obtained by the measurement of magnetic viscosity, showing that it is promising to be ultra- high density recording media.
