Flux jumps, second magnetization peak anomaly, and the peak effect phenomenon in single crystals of Y Ni 2 B 2 C and Lu Ni 2 B 2 C

摘要: We present magnetization measurements in single crystals of the tetragonal $\mathrm{Y}{\mathrm{Ni}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ compound, which exhibit phenomenon peak effect as well second anomaly for $Hg0.5\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ $(H\ensuremath{\Vert}c)$. At lower field $(50\phantom{\rule{0.3em}{0ex}}\mathrm{mT}lHl200\phantom{\rule{0.3em}{0ex}}\mathrm{mT})$, we have observed presence flux jumps, seem to relate a structural change local symmetry line lattice (a first-order reorientation transition across some parts sample, range 100 150 mT). These jumps are also crystal $\mathrm{Lu}{\mathrm{Ni}}_{2}{\mathrm{B}}_{2}\mathrm{C}$ $H\ensuremath{\Vert}c$ region from $2\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}25\phantom{\rule{0.3em}{0ex}}\mathrm{mT}$, compatible with occurrence at cleaner this compared those $\mathrm{Y}{\mathrm{Ni}}_{2}{\mathrm{B}}_{2}\mathrm{C}$. Vortex phase diagrams drawn and show that ordered elastic glass spans larger part $(H,T)$ space former latter, thereby, reaffirming difference relative purity two samples.