Regular Papers
Vacancy Induced Ferromagnetism of MgO in MgB2 Superconductor
2014 年 39 巻 3 号 p. 331-334
詳細
2014 年 39 巻 3 号 p. 331-334
MgB2 was mechanically milled by a planetary ball mill. Rotation speeds were selected from 0 to 150 rpm. Magnetization measurements were performed by Quantum design’s SQUID magnetometer. The milled samples above 100 rpm showed ferromagnetism at 300K. The enhancement of flux pinning property at 20K was observed for milled sample at 150 rpm under 0 field and 10 kOe. These results may be due to the oxygen vacancies in the MgO1-δ nano-particles in the MgB2 host material, since the ferromagnetism was weakened by the sintering in air at 573 K.
