RESUMO
The structural, magnetic, and thermophysical properties of cation-substituted sulfides Gd(X)Mn(1-X)S (0.04 ≤ X ≤ 0.25) with the NaCl-type face-centered cubic lattice have been investigated. The range of existence of long-range antiferromagnetic order has been established. The anomalies observed in the temperature dependence of the specific heat correspond to the temperatures of the magnetic phase transition. The anomaly in the specific heat caused by electron transitions between the 4f levels and d band states has been observed. It has been found that the coefficient of thermal expansion decreases with increasing concentration of substituents in the magnetically ordered region and remains nearly invariable in the paramagnetic phase.
Assuntos
Gadolínio/química , Manganês/química , Modelos Químicos , Modelos Moleculares , Enxofre/química , Simulação por Computador , Campos Magnéticos , Soluções , Temperatura , Condutividade TérmicaRESUMO
Magnetization of the cation-substituted Co(x)Mn(1 - x)S sulfides upon cooling in zero and 100 Oe magnetic fields at the temperatures 4-300 K has been measured. Permittivity of these materials at frequencies from 1 to 100 kHz in magnetic and dc electric fields in the 100-300 K temperature range has been determined. Change in the dielectric permittivity under an external magnetic field is found to have a maximum in the temperature ranges of T1 ~ (110-120 K) and T2 ~ (230-250 K). Formation of spontaneous magnetic moment and the rise of magnetic susceptibility are revealed at the same temperatures in the Co(x)Mn(1- x)S solid solutions. Features of the magnetoelectric properties of the sulfides have been explained by orbital ordering.
