Hiroshi Yoshie

Nuclear Magnetic Resonance of RCo5. II. R=Y, Tb, Dy and Ho

The nuclear magnetic resonance of 59 Co nuclei in magnetic domains of RCo 5 (R=Y, Tb, Dy and Ho) has been measured under external fields up to 55 kOe at 4.2 K. To assign the observed NMR signals to each Co site, the 59 Co nuclear magnetic resonance of R(Co 1- x Ni x ) 5 , has also been measured under the same conditions. From the NMR study of YCo 5 , we have found that the cobalt hyperfine field at the 2 c site has the positive sign (15 kOe) in contrast to the negative sign (-92 kOe) at the 3 g site. This result suggests that the cobalt atoms at the 2 c site in YCo 5 have large orbital moments.

Nuclear Magnetic Resonance Study of RCo5. I. R=Gd and Y

The nuclear magnetic resonance of 59 Co nuclei in magnetic domains of GdCo 5 , GdCo 5- x Ni x ( x =1, 2, 3 and 4) and Gd 1- x Y x Co 5 ( x =0.3, 0.5, 0.7 and 1.0) has been measured under external fields up to 55 kOe at 4.2 K. From the NMR study of GdCo 5 , we found that the cobalt hyperfine field at the 2c site has the positive sign in contrast to the negative sign at the 3g site. This result suggests that the cobalt atoms at the 2c sites in GdCo 5 have large orbital moments.

Nuclear Magnetic Resonance Study of YCo3

The nuclear magnetic resonance of 59 Co nuclei in magnetic domains of YCo 3- x Ni x (0≦ x ≦1) has been measured under external magnetic fields up to 55 kOe at 4.2 K. The hyperfine fields at the 3b, 6c and 18h sites in YCo 3 are found to be 35 kOe, 61 kOe and -42 kOe, respectively. The nuclear magnetic resonance of YCo 3- x Ni x with x =0.65, 0.8 and 1.0 under external magnetic fields shows a nearly paramagnetic state of Co atoms. Consistently, the magnetic moment of these compounds rapidly drops down around these concentrations.

The Magnetic Properties of Pseudo-Binary Compounds, Gd(Fe1-xMnx)2 and Gd6(Fe1-yMny)23

The pseudo-binary compounds Gd(Fe 1- x Mn x ) 2 have been investigated. The crystal structures are C-15 for x ≤0.2 and x ≥0.9, X-structure for 0.4≤ x ≤0.7 and mixture (C-15 and X-structure) for x =0.3 and 0.8, respectively. The measurements of X-ray diffraction, magnetic measurement, NMR and Mossbauer effect were carried out for Gd(Fe 1- x Mn x ) 2 . In order to compare X-structure with Th 6 Mn 23 -structure the pseudo-binary compounds Gd 6 (Fe 1- y Mn y ) 23 have been prepared and also investigated. If X-structure is assumed to be Th 6 Mn 23 -structure, by the structure change from C-15 to X-structure the 48% of Gd atoms are educed in X-structure.

Nuclear Magnetic Resonance of GdCo3

The nuclear magnetic resonance of 59 Co nuclei in magnetic domains of GdCo 3 has been measured under external magnetic fields up to 55 kOe at 4.2 K. In order to assign the observed NMR signals to each Co site, the 59 Co nuclear magnetic resonance of Gd(Co 1- x T x ) 3 where T stands for Ni and Fe, has also been measured under the same conditions. The 59 Co hyperfine fields at the 3 b , 6 c and 18 h sites in GdCo 3 have been measured as 80 kOe, -58 kOe and -80 kOe, respectively. The orbital contribution to the magnetic moment of Co atoms in YCo 3 is also discussed from NMR and neutron diffraction data.

Nuclear Magnetic Resonance of 89Y in Intermetallic Compounds Y(Fe1-xMnx)2

The NMR spectra of 89 Y have been observed at 4.2 K to investigate the magnetic properties of Y(Fe 1- x Mn x ) 2 . There are two kinds of Mn moments in low Mn-concentrations; one is antiparallel to the Fe moment and estimated to be 0.5 µ B per Mn (low spin state), and the other is parallel to the Fe moment and has 2.7 µ B per Mn (high spin state).

Nuclear Magnetic Resonance of RCo5. III. R=Ce and Sm

The nuclear magnetic resonance of 59 Co nuclei in magnetic domains of CeCo 5 and SmCo 5 has been measured under external magnetic fields up to 55 kOe at 4.2 K. In order to assign the observed NMR signals to each Co site, the 59 Co nuclear magnetic resonance of Ce(Co 1- x Ni x ) 5 and Sm(Co 1- x Ni x ) 5 has also been measured under the same conditions. From the NMR study of these cornpounds, we have found that the 59 Co hyperfine field at the 2 c site in CeCo 5 has a very large orbital contribution.

Nuclear magnetic resonance study of RCo5 = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy and Ho

Abstract The nuclear magnetic resonance of 59 Co nuclei in magnetic domains of RCo 5 (R = Y, Ce, Pr, Sm, Gd, Tb, Dy and Ho) has been measured under external fields up to about 55 kOe at 4.2 K. To assign the observed NMR signals to each Co site, the 59 Co nuclear magnetic resonance of R(Co 1− x ) 5 has also been measured under the same conditions. The results of NMR studies show that the orbital contribution to the 59 Co hyperfine field is very large at the 2c site in RCo 5 .

The Nuclear Magnetic Resonances of 55Mn in RMn2 and (Y1-xGdx)6Mn23 (R=Gd, Tb, Ho: 0 ≦x ≦1)

The nuclear magnetic resonances of 55 Mn nuclei have been observed in the intermetallic compounds RMn 2 and (Y 1- x Gd x ) 6 Mn 23 where R is Gd, Tb, Ho and 0 ≦ x ≦1. The Mn moments in these compounds were estimated to be larger (0.8–1.3 µ B /Mn) than those obtained from the magnetic measurements of R 6 Mn 23 (0.4 µ B /Mn). The hyperfine fields at 55 Mn nuclei in RMn 2 are expressed as the linear relation of ( g -1) J . The Gd-contribution to the hyperfine fields at 55 Mn nuclei in (Y 1- x Gd x ) 6 Mn 23 may be 13 kOe at most.

Magnetic properties of the hypothetical compound YFe5

Abstract The magnetic properties of the hypothetical compound YFe5 are obtained by extrapolating the values of lattice constants, saturation magnetizations, Ms, and 57 Fe hyperfine fields, Beff, for Y(T1−xFex)5 (T=Co and Ni). For the hypothetical compound YFe5, the average Fe moment and 57 Fe hyperfine fields are almost consistent with the estimated values based on an interpolation of the concentration dependence of the Y–Fe compounds assuming that the values of Ms and the average Beff show a maximum at x=0.7 and 0.81, respectively.