Suppression of antiferromagnetic order in low-dopped ceramic samples La_{2-x}Sr_{x}CuO_{4}

Possible influence of spatially inhomogeneous distribution of strontium impurities on the temperature of antiferromagnetic (AFM) ordering in ceramic samples La2-xSrxCuO4 has been revealed.

Torque magnetometry studies of new low temperature metamagnetic states in ErNi_{2}B_{2}C

The metamagnetic transitions in single-crystal ErNi$_2$B$_2$C have been studied at 1.9 K with a Quantum Design torque magnetometer. The critical fields of the transitions depend crucially on the angle between applied field and the easy axis [100]. Torque measurements have been made while changing angular direction of the magnetic field (parallel to basal tetragonal $ab$-planes) in a wide angular range (more than two quadrants). Sequences of metamagnetic transitions with increasing field are found to be different for the magnetic field along (or close enough to) the easy [100] axis from that near the hard [110] axis. The study have revealed new metamagnetic states in ErNi$_{2}$B$_2$C which were not apparent in previous longitudinal-magnetization and neutron studies.

Torque magnetometry study of metamagnetic transitions in single-crystal HoNi2B2C at Tapprox 1.9 K

Metamagnetic transitions in single-crystal rare-earth nickel borocarbide HoNi$_2$B$_2$C have been studied at Tapprox 1.9 K with a Quantum Design torque magnetometer. This compound is highly anisotropic with a variety of metamagnetic states at low temperature which includes antiferromagnetic, ferrimagnetic, non-collinear and ferromagnetic-like (saturated paramagnet) states. The critical fields of the transitions depend crucially on the angle $theta$ between applied field and the easy axis [110]. Measurements of torque along the c-axis have been made while changing the angular direction of the magnetic field (parallel to basal tetragonal $ab$-planes) and with changing field at fixed angle over a wide angular range. Two new phase boundaries in the region of the non-collinear phase have been observed, and the direction of the magnetization in this phase has been precisely determined. At low field the antiferromagnetic phase is observed to be multidomain. In the angular range very close to the hard axis [100] ($-6^{circ} lesssimphi lesssim 6^{circ}$, where $phi$ is the angle between field and the hard axis) the magnetic behavior is found to be ``frustrated with a mixture of phases with different directions of the magnetization.