Anomalous magnetoresistance in antiferromagnetic polycrystalline materials R2Ni3Si5 (R=rare earth)

Abstract

Magnetoresistance (MR) studies on polycrystalline R2Ni3Si5, (R=Y, rare earth) which order antiferromagnetically at low temperatures, are reported here. MR of the Nd, Sm, and Tb members of the series exhibit positive giant magnetoresistance, largest among polycrystalline materials (85%, 75%, and 58% for Tb2Ni3Si5, Sm2Ni3Si5, and Nd2Ni3Si5, respectively, at 4.4 K in a field of 45 kG). These materials have, to the best of our knowledge, the largest positive GMR reported ever for any bulk polycrystalline compounds. The magnitude of MR does not correlate with the rare earth magnetic moments. We believe that the structure of these materials, which can be considered as a naturally occurring multilayer of wavy planes of rare earth atoms separated by Ni–Si network, plays a role. The isothermal MR of other members of this series (R=Pr,Dy,Ho) exhibits a maximum and a minimum, below their respective TN’s. We interpret these in terms of a metamagnetic transition and short-range ferromagnetic correlations. The short-range ferromagnetic correlations seem to be dominant in the temperature region just above TN.

Magnetism and charge density waves in RNiC2(R=Ce,Pr,Nd)

“…Below this temperature, the magnetoresistance changes its sign and magnitude. This is a typical picture of the modification of the scattering rate in the vicinity of the magnetic ordering temperature [56][57][58] ; above T N the reduction of resistance can be attributed to the field induced ordering of the local magnetic moments, resulting in the quenching of the spin fluctuations and effectively a decrease of the related scattering mechanism. On the other side of the transition, below T N , the magnetic field induces a partial reorientation of the local spins and perturbs the antiferromagnetic order, which results in the increase of the scattering rate and, consequently, of the electrical resistance.…”

Synthesis, magnetic properties, and colossal magnetoresistance ofEu13.97Gd0.03MnSbChan1, Kauzlarich2, Klavins3 et al. 2000Phys. Rev. B332330View full textAdd to dashboardCite

“…This is in contrast to the antiferromagnetic polycrystalline materials R 2 Ni 3 Si 5 (Rϭrare earth͒ where positive giant magnetoresistance is shown and a metamagnetic transition and short-range ferromagnetic correlations are responsible for the magnetoresistance. 18 In fact, most antiferromagnetic materials have been shown to exhibit positive magnetoresistance. 19,20 The contribution of spin fluctuation from the magnetic polarons may be responsible in this system.…”

Crossover from charge density wave stabilized antiferromagnetism to superconductivity in Nd1−xLaxNiC2 compounds

“…Inset: expanded view for the low temperature region to highlight the collision of AFM and SC regions at a possible quantum critical point marked by red arrow. 5b)) however, the CDW transition is no longer observed, thus the spin fluctuations are expected to be the main driving force of the magnetoresistance [57][58][59] . The application of a magnetic field reduces the height of the resistivity hump observed below T N , which can be attributed to a partial reorientation of the magnetic moments and a reduction of the magnetic entropy.…”