Papers by Keyword: Spontaneous Magnetostriction

Abstract: The thermal expansion and magnetic properties of Gd₂Fe_16.5Cr_0.5 compound have been investigated by means of X-ray diffraction and magnetization measurements. The Gd₂Fe_16.5Cr_0.5 compound has a rhombohedral Th₂Zn₁₇-type structure. The Curie temperature of Gd₂Fe _16.5 Cr _0.5 compound is about 560K. This value is about 50K higher than that value of the mother compound Gd₂Fe₁₇. A small average thermal expansion coefficient, = 1.65×10-6/K, and a negative average thermal expansion coefficient, = -1.46×10-5/K, were found in Gd₂Fe _16.5 Cr _0.5 compound by X-ray diffraction in the temperature range 294 - 514K, and 514-613K, respectively. There exists anisotropic strong spontaneous magnetostriction in the magnetic state of Gd₂Fe _16.5 Cr _0.5 compound.

Abstract: Spontaneous magnetization Ms of the ferromagnetic compound Mn5Ge3 with the Curie temperature TC=305 K has been studied in the temperature range from 2 to 400 K. The relationships between the magnetic part of the heat capacity (CMAG), the magnetic part of the volume thermal expansion coefficient (TEC) MAG, and the Ms for the compound Mn5Ge3 have been considered. It has been found that the magnetic part of the heat capacity can be well approximated by the dependence CMAG(T)=a×|dMs2/dT|–b×|dMs4/dT| with a>0 and b>0, and the magnetic part of the TEC, by the dependence  MAG=C1×dMs2/dT+C2×dMs4/dT with C1<0 and C2>0 in the whole temperature. It is assumed that the main sources in the formation of the observed CMAG(T) and MAG(T) dependences are the changes in the elastic, magnetoelastic, magnetovolume, and magnetostatic energies of the sample that appear as a result of the spontaneous magnetostrictive deformation with temperature changing.

Abstract: Magnetic, electronic, structural and magnetovolume properties of the R2Fe17-xMx (R = Y, Lu, Ce; M = Si or Al) compounds were studied. We pioneered to apply electronic band parameters determination to account for the anomalous volume dependence of ferromagnetism in these compounds.