The Phase Relations of the Co-Ni-In Ternary System at 673 K and 873 K and Magnetic Properties of Their Compounds

The phase relationships of the ternary Co-Ni-In system at 673 K and 873 K were investigated by means of powder X-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy, and optical microscopy. Though CoIn2 does not exist at 873 K, the ternary solid solution Co1−xNixIn2 exists at both 673 K and 873 K with different composition ranges. The Rietveld refinements were carried out to investigate the crystal structure of Co1−xNixIn2 (x = 0.540, and 0.580) and Ni2−xCoxIn3 (x = 0.200). The magnetization dependence of temperature (MT) curves of Ni2−xCoxIn3 (x = 0.200) and Co1−xNixIn2 (x = 0.540) are similar to those of the ferromagnetic shape memory alloys Ni-Mn-A (A = Ga, Sn, and In), but do not undergo martensitic transformation. The maximum magnetic entropy changes in Ni2−xCoxIn3 (x = 0.200) and Co1−xNixIn2 (x = 0.540) under 3T are 1.25 and 1.475 J kg−1K−1, respectively.

Inverse Brillouin Function and Demonstration of Its Application

The Brillouin function arises in the quantum theory of paramagnetic materials, where it describes the dependence of the magnetization on the externally applied magnetic field and on the temperature of the system. There is no closed form exact analytical expression for the inverse Brillouin function, however, there have been several approximations proposed. In this work, we first compare relative errors and simplicity of several approximations for the inverse Brillouin function. Next, we demonstrate the application of the inverse Brillouin function by determining the Hamiltonian of the system using the simulation data of the magnetization dependence on the temperature. Then we compare the Hamiltonian that was used to set up the simulation with the Hamiltonian determined from the magnetization temperature dependence and an approximation to the inverse Brillouin function. We found that some of the approximations for the inverse Brillouin function can be used to accurately predict the Hamiltonian of the system given the magnetization dependence on temperature.

Ferromagnetic Co-P Powders with Nanodiamond and Corundum Precipitates

Powders of Ñî-Ð alloy with ultradispersed corundum (Al2O3) and detonation nanodiamond (DND) precipitates were synthesized by chemical reduction. The products were characterized by X-ray diffraction and scanning electronic microscopy. The shape of the particles was spherical and they were ferromagnetic. Magnetization dependence on field in applied fields of up to 40 kOe and magnetization dependence on temperature in the temperature range from 2 to 300 K were measured. Influence of precipitates on magnetic properties was studied.