Journal of Alloys and Compounds
The influence of magnetic fields on the mechanical loss (Q(-1)) of Terfenol-D/PbZr(0.52)Ti(0.48)O(3)/Terfenol-D three-layer laminated composites is investigated systemically using the technique for measuring the resonance magnetoelectric (ME) effect. The results indicate that Q(-1) varies non-monotonically with dc magnetic fields and shows a maximum near 500 Oe for all the samples with different layer thickness ratios (n) of Terfenol-D (Tb(0.3)Dy(0.7)Fe(1.92)). Considering various kinds of mechanical energy dissipation, it is found that Q(-1) is mainly dominated by the mechanical damping due to the domain wall motion in Terfenol-D under the actions of dc and ac magnetic fields as well as the stress at the interface. In addition, the effect of eddy current losses on the energy dissipation of the system is also discussed. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Magnetoelectric composite;Mechanical energy dissipation;Domain wall;motion;magnetomechanical damping capacity;terfenol-d;magnetostriction;alloys;tb0.27dy0.73fe2;tb0.3dy0.7fe1.95
Communications in Theoretical Physics
By successively taking into account various interactions for d(2) ions in trigonally distorted cubic crystal fields, detailed analyses, derivations and calculations of the zero-field splitting (ZFS) and g factors of the ground state have been carried out; and their physical essentials and origins have been clearly revealed. The mistakes and shortcomings in some references have been corrected and improved. The calculated results are in excellent agreement with experimental data and much better than those of previous work. It is found that both the combined action of the trigonal field and spin-orbit interaction and the interaction between the ground state and excited states are quite necessary for causing ZFS of the ground state, and both the spin-orbit interaction and the admixture between the ground state and excited states are necessary for causing the deviation of g factors of the ground state from spin-only values.
关键词:
zero-field splitting;g factors;d(2) ions;crystal field;combined;action;admixture of wavefunction
Physics Letters A
The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D, in which A, B, C and D are four different magnetic ions and form four different sublattices, are studied by using the Ising model. And the Ising model was dealt with standard mean-field approximation. The regions of concentration in which two compensation points or one compensation point exit are given in c-a, b-c and a-b planes. The phase diagrams of the transition temperature T-c and compensation temperature T-comp are obtained. The temperature dependences of the magnetization are also investigated. Some of the result can be used to explain the experimental work of the molecule-based ferro-ferrimagnet ((NiaMnbFecII)-Mn-II-Fe-II)(1.5) [Cr-III (CN)6] - zH(2)O. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
mixed ferro-ferrimagnet;Ising model;four sublattices;phase diagram;transition temperature;compensation temperature;magnetic-properties;prussian blue;alloy
Communications in Theoretical Physics
In this paper, we present a particle-cluster model for a two-dimensional fractal aggregation with the nearest neighbor and next-nearest neighbor interactions in external fields. The external field is described by the probability P. Our computer simulation results show that the threshold concentration is P-c(a) = 0.59 +/- 0.02 and the fractal dimension is D-c = 1.67 +/- 0.03 at this concentration. In comparison with previous results with nearest neighbor interaction only, we find that D-c is the same, but P-c(a) is smaller, which is reasonable, since the connectivity has been changed significantly.
关键词:
diffusion-limited aggregation;continuum approximation;clusters;morphology;zinc
Physica B-Condensed Matter
A formalism is presented that enables the calculation of atomic charge and current densities in Russel-Saunders states of free atoms and ions in terms of scalar and vector spherical harmonics. The electric and magnetic fields generated by the multipole components of charge and current distributions are easily calculated. They are found to have the same multipolarity as their generating sources and Maxwell's equations are satisfied component by component. Calculations of these fields for hydrogenlike atoms and specific transition-metal and rare-earth ions are presented using realistic analytic radial wave functions. (C) 2008 Elsevier B.V. All rights reserved.
关键词:
ions;moments
