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We have synthesized a new series of layered oxyselenides La2O3(Mn1−xCox)2Se2 through a solid state reaction method. Their structure and physical properties were studied through powder X-ray diffraction, electric transport measurements, absorption spectroscopy, bulk magnetization and specific heat experiments. These compounds crystallize in layered structures with the space group I4/mmm. All the samples present semiconducting or insulating behavior with the activation energy ranging from 0.134 eV to 0.400 eV. The ferromagnetic (FM) component is induced as Co enters the lattice, and the FM component raises to its maximum when x is 0.6. The competing of FM and antiferromagnetic (AFM) components led to the emergence of a spin-glass like behavior in the intermediate alloys.

Using a modified dynamic Monte Carlo renormalization group method, the two- dimensional kinetic Ising model is studied, and the dynamic critical exponent is obtained. The critical temperature of phase transition can be obtained by the renormalization method for the correlation function. In the method we used, the correlation function is replaced with the absolute value of the magnetization, and it is found that the evolution of the absolute value of the magnetization over time satisfies the power-law form. It is found that the value of the dynamic critical exponent tends to be a stable value in the form of a power-law function as the scale of the system increases. The dynamic critical exponent obtained is z ≃ 2 . 15 . When the modified dynamic Monte Carlo renormalization group method is applied to the two-dimensional Glauber model, the obtained dynamic critical exponent is z ≃ 2 . 25 .

We investigated the physical properties of the cobalt doped layered oxyselenides BiCu1-xCoxSeO. 5% Co doping led to a large increase in the Seebeck coefficient which should be attributed to the magnetic interactions with the magnetic moment carried by Co atoms. The carrier-type of the material is changed from p-type to n-type with 20% Co doping. We studied the thermoelectric property of Bi0.95Ca0.05Cu0.95Co0.05SeO. The dual-doping sample exhibits higher Seebeck coefficient than Ca single doped sample and the ZT was enhanced remarkably. A maximum ZT value of 0.11 was achieved for Bi0.95Ca0.05Cu0.95Co0.05SeO at 300 K.

In this paper, we provide a new approach to create weighted scale-free networks by the method of weight redistribution. In our model, from an Erdös and Rényi random graph, with every edge having the same weight one, along with the total number of vertices and the total weight of all edges constant, we redistribute the weight based on our rules. When the network is dynamically stabilized, we find that both the degree and the strength distributions of our model satisfy the power-law form respectively, with the exponents approximating one. To have the power-law exponents tunable, we give each vertex an intrinsic strength initially. When the improved model is dynamically stabilized, we find the power-law exponents become tunable. Numerical results verify our theoretical analysis.