MAGNETIC STUDY OF SMCO5, PRCO5, SMCO4B, AND SM3CO11B4 UNDER PULSE HIGH-FIELD

Magnetization curves and hysteresis loops for field-oriented powders of Sm(n+1)Co3n+5B2n (n = 0, 1, and 3) and PrCo5 were measured at T = 4.2 K and partly at 77 K, under a strong pulsed field up to 36 T. Magnetic measurements for Sm(n+1)Co3n+1B2n (n = 1, 2, and 3) compounds were also performed. Huge anisotropy fields of 120 T for SmCo4B and of 130 T for Sm2Co7B3 were obtained. The Sm sublattice anisotropy of SmCo4B was found to be larger than that of SmCo5. To explain this, the Sm f-electron state for n greater-than-or-equal-to 2 of Sm(n+1)Co3n+5B2n has been expected to change from that for n less-than-or-equal-to 1. Huge coercivities of 8 T and 27.5 T were observed at T = 4.2 K for SmCo4B and for Sm2Co7B3 respectively. Magnetization processes for field-oriented PrCo5 at T = 4.2 K were found to be similar to those of Nd2Fe14B at T = 4.2 K.