Flux jumps, Second Magnetization Peak anomaly and the Peak Effect phenomenon in single crystals of $YN{i}_2{B}_{2}C$ and $LuN{i}_2{B}_{2}C$

Abstract

We present magnetization measurements in single crystals of the tetragonal $YN{i}_2{B}_{2}C$ compound, which exhibit the phenomenon of peak effect as well as the second magnetization peak anomaly for H $>$ 0.5T (H $||$ c). At the lower field (50mT $<$ H $<$ 200mT), we have observed the presence of flux jumps, which seem to relate to a structural change in the local symmetry of the flux line lattice (a first order re-orientation transition across a local field in some parts of the sample, in the range of 100mT to 150mT). These flux jumps are also observed in a single crystal of $LuN{i}_2{B}_{2}C$ for H $||$ c in the field region from 2 mT to 25 mT, which are compatible with the occurrence of a re-orientation transition at a lower field in a cleaner crystal of this compound, as compared to those of $YN{i}_2{B}_{2}C$. Vortex phase diagrams drawn for H $||$ c in $LuN{i}_2{B}_{2}C$ and $YN{i}_2{B}_{2}C$ show that the ordered elastic glass phase spans a larger part of (H, T) space in the former as compared to latter, thereby, reaffirming the difference in the relative purity of the two samples.

11 pages, 14 figures