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Abstract: Large sized α-Li3Fe2(PO4)3 single crystals with high quality are successfully grown by a flux method. Magnetic behaviors of the grown crystals are investigated by means of magnetic susceptibility, magnetization, and heat capacity measurements along different directions. The results confirm that α-Li3Fe2(PO4)3 exhibits weak ferrimagnetic behaviors at low temperature, which are in good agreement with those reported previously. However magnetic anisotropy is confirmed for the first time, suggesting that the c-axis is the likely magnetic easy axis and the a-axis is the magnetic hard one. Two anomalies are clearly observed in magnetic susceptibility along the a-axis and heat capacity data at zero field, suggesting the appearance of two successive magnetic transitions at ~26 and ~22K in the system. [Copyright &y& Elsevier]

Abstract: This paper presents a review and results of comparative study of the influence of Gd on some physical properties of (R 0.9 R′0.1)1−x Gd x Co2 solid solutions with R=Dy, Ho and R′=Er, Ho and x varied from 0.05 to 0.15. Powder X-ray diffraction analysis performed at room temperature revealed that all studied solid solutions solidify with the formation of a Laves-phase MgCu2-type structure (space group Fd−3m). The magnetization behavior and the magnetic transition are analyzed in terms of the Landau theory. The studies of magnetic properties and heat capacity showed that a relatively small Gd addition significantly increases T C of the compounds. The maximum percentage increase in T C, namely, ~43% was observed for (Ho0.9Er0.1)1−x Gd x Co2. However, the highest temperature was noted for the (Dy0.9Ho0.1)0.85Gd0.15Co2 solid solution; it is T C=183.4K. Below the ordering temperature, all samples are ferrimagnetically ordered; at high temperatures, they are Curie–Weiss paramagnets. Moreover, a small Gd addition eliminates the field-induced magnetic transition near T C and, as consequence, transforms the nature of magnetic transition from the first- to second-order. The magnetocaloric effect has been estimated in terms of both isothermal magnetic entropy and adiabatic temperature changes. The highest adiabatic temperature change ΔT ad=3K and highest isothermal entropy change ΔS mag=12.1J/kgK were observed for (Ho0.9Er0.1)0.95Gd0.05Co2 at ~90K in magnetic fields of 2T and 3T, respectively. A decrease in the entropy change has been observed with increasing Gd content in all studied samples. The smallest values of ΔS mag were observed for the (Dy0.9Ho0.1)1−x Gd x Co2 solid solutions. Under an external field change of from 0 to 3T, the maximum entropy change for (Dy0.9Ho0.1)1−x Gd x Co2 compounds decreases from 6.9at x=0.05–4.3J/kgK at x=0.15. The refrigerant capacity for all solid solutions (with 0.05≤x≤0.15) is reported. The effect of increasing Gd content in the solid solutions on their magnetic and magnetocaloric properties is discussed. [Copyright &y& Elsevier]

Abstract: A magnetic phase diagram of Fe1−х Zn х Cr2S4 solid solutions was studied. The temperature and concentration ranges of existence of magnetoactive phases based on ferrimagnet FeCr2S4 (0≤х≤0.63), antiferromagnet ZnCr2S4 (0.73≤х≤1), and a spin glass (0.63≤х≤0.73) were determined. The concentration dependences of the saturation magnetic moments and Curie temperatures of the solid solutions synthesized were investigated experimentally and theoretically. [Copyright &y& Elsevier]