X-ray diffraction (XRD) and magnetization measurements were employed to investigate the effect of Mn substitution for Co on the structure and magnetic properties of Y2Co17−xMnx compounds with x=0–8. XRD patterns show that all samples are single phase with a hexagonal Th2Ni17-type structure. The substitution of Mn for Co in Y2Co17−xMnx compounds leads to a monotonic increase in unit cell volume. The saturation magnetization remains nearly constant for x⩽3, then decreases quickly with increasing Mn content; this can be explained by the change of the 3d energy band structure and an electron transfer process. The Curie temperature TC is found to decrease rapidly with increasing Mn concentrations. X-ray diffraction measurement on magnetically aligned Y2Co17−xMnx compounds exhibit an easy-plane type of magnetic anisotropy at room temperature for x=0 and an easy-axis type of magnetic anisotropy at room temperature with x=1–7. Substitution of Mn for Co leads to a change of the magnetocrystalline anisotropy of the...

Structure and magnetic properties of Y2Co17-xMnx (x=0-8) compounds

Magnetic properties of Sm2Co17-xCrx (0 <= x <= 3.0) compounds

X-ray diffraction (XRD) and magnetization measurements were employed to investigate the effect of Mn substitution for Co on the structure and magnetic properties of Ce2 Co17-x Mnx compounds with x = 0, 1, 2, 3, 4. XRD patterns show that all samples are single phase with the hexagonal Th2 Ni17 -type structure. The substitution of Mn for Co in Ce2 Co17-x Mnx compounds leads to a monotonic increase in unit-cell volume. The saturation magnetization at 5 K and the Curie temperature TC decrease monotonically with increasing Mn content. X-ray diffraction measurements on magnetically aligned Ce2 Co17-x Mnx powders with x = 0-4 exhibit an easy-axis type of magnetic anisotropy at room temperature. The substitution of Mn for Co leads to a change of the magnetocrystalline anisotropy of the Co sublattice from the basal plane to c -axis and strongly increases the uniaxial anisotropy of Ce2 Co17-x Mnx compounds. The magnetocrystalline anisotropy field HA is found first to increase and then decrease with increasing Mn concentration, attaining a maximum value of 30.1 kOe at x = 2.

http://iopscience.iop.org/article/10.1088/0953-8984/12/11/315/pdf

The effect of manganese substitution on the magnetic properties of Ce2Co17 compounds

An investigation of the structure and the magnetic anisotropy of R2Co15Al2 (R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm) compounds has been performed by means of x-ray diffraction and magnetization measurements. X-ray diffraction shows the prepared compounds to be single phase, having the hexagonal Th2Ni17-type structure for R=Y, Ho, Er, and Tm and the rhombohedral Th2Zn17-type structure for R=Ce, Pr, Nd, Gd, Tb, and Dy. Except for the Ce compound, the unit-cell volumes of R2Co15Al2 compounds decrease in accordance with the lanthanide contraction. Substitution of Al for Co in R2Co17 leads to a decrease of the saturation magnetization at 1.5 K and Curie temperature. The exchange-coupling constants JCo–Co and JR–Co have been calculated by using the method based on magnetic ordering temperature. It is found that the JR–Co has a small dependence on the R elements and is almost not affected by the Al substitution. The Ce compound is found to exhibit an anomalous lattice parameter and magnetic characteristi...

Magnetic properties of R2Co15Al2 compounds with R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm

Spin reorientation and magnetic anisotropy in Y2Co17−xCrx (x = 1.17–3.0) compounds

The influence of Si substitution for Co on the structure and magnetic properties of and (x = 0-3) compounds were investigated by means of x-ray diffraction and magnetization measurements. X-ray diffraction patterns demonstrate that all samples are single phase with the hexagonal -type structure for and the rhombohedral -type structure for compounds, except for with a small amount of impurity phases. The unit-cell volume is found to decrease linearly with increasing Si concentration in both series. The Curie temperature decreases monotonically with increasing Si concentration at an approximate rate of 205 and 175 K per Si atom for the and compounds, respectively. The saturation magnetic moments of (R = Y, Pr) decrease with increasing Si content and the decline rates are larger than that expected as a simple dilution. For , the substitution of Si has a significant effect on the magnetocrystalline anisotropy of the Co sublattice, and changes the easy magnetization direction from the basal plane to the c-axis at room temperature. For , the Si substitution has not changed the easy magnetization direction at room temperature. However, the spin-reorientation transitions from the basal plane to the c-axis for this series with were observed above room temperature with increasing temperature. The spin-reorientation temperature first decreases with increasing Si content and then increases at higher x values (x > 2). The origin of this spin reorientation is interpreted by the competition between the Pr sublattice anisotropy and the Co sublattice anisotropy. This has been confirmed by the magnetocrystalline anisotropy measurements on .

https://iopscience.iop.org/article/10.1088/0953-8984/10/11/008/pdf

Xin-fa Ruan

Papers

Structure and magnetic properties of ( x = 0-3) compounds with R = Y and Pr