Magnetoresistance and magnetic ordering in praseodymium and neodymium hexaborides

摘要: The magnetoresistance Δρ/ρ of single-crystal samples praseodymium and neodymium hexaborides (PrB6 NdB6) has been measured at temperatures ranging from 2 to 20 K in a magnetic field up 80 kOe. results obtained have revealed crossover the regime small negative paramagnetic state large positive magnetoresistive effect magnetically ordered phases PrB6 NdB6 compounds. An analysis dependences Δρ(H)/ρ made it possible separate three contributions for compounds under investigation. In addition main contribution, which is quadratic (−Δρ/ρ ∝ H2), linear contribution (Δρ/ρ H) nonlinear ferromagnetic found. Upon transition state, component becomes dominant, whereas completely suppressed commensurate phase these presence several components explained by assuming that, antiferromagnetic NdB6, nanoregions (ferrons) are formed 5d band vicinity rareearth ions. origin interpreted terms Yosida model, takes into account scattering conduction electrons localized moments rare-earth Within approach used, local susceptibility χloc estimated. It demonstrated temperature range TN < T K, behavior investigation can be described with good accuracy Curie-Weiss dependence (T − Θp)−1.