K. Ichinose

141Pr and 159Tb NMR study of the magnetic properties of RCo5+x (R = Pr and Tb)

Abstract 141 Pr and 159 Tb spin-echo NMR measurements have been done on PrCo 5 and TbCo 5.1 compounds. In both compounds, domain signals have been distinguished from domain wall signals under external fields. For TbCo 5.1 , the hyperfine field and electric quadrupole interaction parameter of Tb obtained by NMR are in good agreement with those evaluated from the analysis of the magnetization of the compound on the basis of the crystalline electric field (CEF) interaction including the exchange interaction between the rare earth and Co. On the contrary, Pr hyperfine field of 2251 kOe in PrCo 5 is much smaller than that evaluated from the CEF analysis.

NMR study of RCo3B2 (R = Y, Sm)

59 Co NMR spectra have been measured in RCo 3 B 2 (R = Y, Sm) under external magnetic field up to 1.8 T at 4.2 K. The 59 Co hyperfine fields are estimated as zero and -0.11 T for YCo 3 B 2 and SmCo 3 B 2 , respectively. The Co magnetic moments induced by the spin of R ion are discussed.

NMR study of magnetic properties of Pr2Fe14B

Abstract 141Pr NMR measurements have been done on Pr2Fe14B and (Pr0.9Lu0.1)2Fe14B at 1.4K by the spin-echo method. The observed hyperfine fields in Pr2Fe14B are 2574 and 2803kOe for the f and g sites, respectively, and in (Pr0.9Lu0.1)2Fe14B 2560 and 2804kOe for the f and g sites, respectively. The hyperfine fields due to the 4f shell of the Pr3+ ion were evaluated taking into account the transferred hyperfine field from the Fe sublattice. The magnetic moments of Pr3+ in Pr2Fe14B were estimated to be 2.9 and 3.0μB for the f and g sites, respectively.

Magnetic behavior of PrCo5 hydride

Abstract The hydrogen absorption effects in PrCo5 have been studied from the mean Co moment (μCo) and the mean hyperfine field at 59Co nuclei (Hhf). Hhf decreases gradually, while μCo decreases rapidly upon hydrogen absorption. The proportion of the orbital Co moment to μCo decreases abruptly for the single-phase hydride region.

143Nd NMR study of 3d and 4f magnetism in Nd2(Fe1−xCox)14B and Nd2(Fe1−yNiy)14B

Abstract A systematic NMR study of the effects of Co and Ni substitutions on the 143Nd hyperfine fields in Nd2(Fe1−xCox)14B and Nd2(Fe1−yNiy)14B has been carried out by the spin-echo method in zero external magnetic field. The substitution of Co for Fe leads that the hyperfine field first decreases and then increases, while the substitution of Ni for Fe brings about a significant reduction of the hyperfine field. This decrease, however, is recovered by further substitution of Co for Fe in the Nd2(Fe1−yNiy)14B. An analysis of the Nd hyperfine field based on the saturation magnetization of Nd2(Fe1−xCox)14B and Nd2(Fe1−yNiy)14B compounds leads to a conclusion that the Nd magnetic moment averaged over the f and g sites in the latter is reduced to 2.9 μB for y=0.1 from 3.0 μB for y=0.

NMR study of magnetic properties of (Er1 − xTbx)2Fe14B

Abstract 159 Tb NMR measurements have been made on (Er 1 − x Tb x ) 2 Fe 14 B at 1.4 K. The electric quadrupole splittings change in the vicinity of the spin-reorientation transitions. The hyperfine fields of Tb at the f and g sites increase from 360 and 352 T, respectively, in (Er 0.98 Tb 0.02 ) 14 B, to 367.4 and 356.5 T, respectively, in Tb 2 Fe 14 B.

NMR study of electric hyperfine interaction of rare earth in RFe11Ti (R = Nd, Sm, Tb, Dy, Er and Lu)

Abstract Electric quadrupole interactions of rare earths in RFe 11 Ti (R = rare earth) observed by spin-echo NMR have been analyzed by comparing them with that for 175 Lu in LuFe 11 Ti.