Ya. Mudryk

Phase relationships, and structural, magnetic, and magnetocaloric properties in the Ce5Si4–Ce5Ge4 system

The crystallography, phase relationships, and magnetic properties of the Ce5Si4−xGex alloys with 0≤x≤4 have been investigated by using x-ray powder diffraction and isothermal magnetization measurements. There are three different crystal structures in the Ce5Si4−xGex system: the Zr5Si4-type tetragonal structure with space group P41212 exists from 0≤x<2.15, the Gd5Si2Ge2-type monoclinic structure with space group P1121/a exists at x≈2.225, and the Sm5Ge4-type orthorhombic structure with space group Pnma is found for 2.4<x≤4. The magnetic ordering temperature increases when the tetragonal phase changes to the monoclinic phase, and then it remains composition independent throughout the orthorhombic phase, which is the opposite trend compared to that observed in the heavy lanthanide 5:4 compounds when Ge content increases. Another distinct difference is that Ce5Si4 exhibits an antiferromagnetic ground state while Ce5Ge4 phase orders ferromagnetically, which is reverse compared to the R5Si4−xGex systems where R...

Enhancement of the glass-forming ability by Zr microalloying and its influence on the magnetocaloric properties of bulk amorphous Gd–Co–Al

Microalloying with 1 at. % zirconium dramatically increases the critical size from 3 to 8 mm for Gd-based bulk metallic glasses (BMGs). The enhancement of glass-forming ability originates from the increase in the packing efficiency and high compound forming tendency between Zr and major constituent elements. The maximum magnetic entropy change (−ΔSMmax) and relative cooling power (RCP) of Gd52.5Co18.5Al29−xZrx (x=1) BMG are 9.6 J/kg K and 8.9×102 J/kg, respectively. Heat capacity data demonstrate that the broad magnetic transition arising from topological disorder is responsible for the high RCP of Gd-based amorphous magnetocaloric materials.

Magnetic and magnetothermal properties and the magnetic phase diagram of high purity single crystalline terbium along the easy magnetization direction

The magnetic and magnetothermal properties of a high purity terbium single crystal have been re-investigated from 1.5 to 350 K in magnetic fields ranging from 0 to 75 kOe using magnetization, ac magnetic susceptibility and heat capacity measurements. The magnetic phase diagram has been refined by establishing a region of the fan-like phase broader than reported in the past, by locating a tricritical point at 226 K, and by a more accurate definition of the critical fields and temperatures associated with the magnetic phases observed in Tb.

Magnetic and magnetothermal properties, and the magnetic phase diagram of single-crystal holmium along the easy magnetization direction.

The magnetic and magnetothermal properties of holmium single crystal have been investigated from 4.2 to 300 K in magnetic fields up to 100 kOe using magnetization and heat capacity data measured along the easy magnetization direction, which is the crystallographic b-axis, i.e. [112¯0] direction. The magnetic phase diagram of Ho has been refined by examining data measured using a high purity single crystal.

Magnetostructural transition in Ce(Fe0.975Ga0.025)2 compound

The magnetic and magnetostructural properties of the polycrystalline Ce(Fe0.975Ga0.025)2 have been investigated as a function of temperature and magnetic field. In Ce(Fe0.975Ga0.025)2 the magnetic transition from antiferromagnetic (AFM) to ferromagnetic (FM) state is accompanied by a structural transformation from rhombohedral to cubic structure. Phase coexistence is present during both the temperature and field driven transformations from AFM to FM phase.