Magnetoresistance and magnetic ordering in praseodymium and neodymium hexaborides

Journal Article · Sun Nov 15 00:00:00 EST 2009 · Journal of Experimental and Theoretical Physics

DOI:https://doi.org/10.1134/S1063776109110119· OSTI ID:21443665

Anisimov, M A ^[1]; Bogach, A V ^[2]; Glushkov, V V ^[1]; Demishev, S V; Samarin, N A ^[2]; Filipov, V B; Shitsevalova, N Yu ^[3]; Kuznetsov, A V

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1. Moscow Institute of Physics and Technology (State University) (Russian Federation)
2. Russian Academy of Sciences, A. M. Prokhorov General Physics Institute (Russian Federation)
3. National Academy of Sciences of Ukraine, I. N. Frantsevich Institute for Problems of Materials Science (Ukraine)

The magnetoresistance {Delta}{rho}/{rho} of single-crystal samples of praseodymium and neodymium hexaborides (PrB{sub 6} and NdB{sub 6}) has been measured at temperatures ranging from 2 to 20 K in a magnetic field of up to 80 kOe. The results obtained have revealed a crossover of the regime from a small negative magnetoresistance in the paramagnetic state to a large positive magnetoresistive effect in magnetically ordered phases of the PrB{sub 6} and NdB{sub 6} compounds. An analysis of the dependences {Delta}{rho}(H)/{rho} has made it possible to separate three contributions to the magnetoresistance for the compounds under investigation. In addition to the main negative contribution, which is quadratic in the magnetic field (-{Delta}{rho}/{rho} {proportional_to} H{sup 2}), a linear positive contribution ({Delta}{rho}/{rho} {proportional_to} H) and a nonlinear ferromagnetic contribution have been found. Upon transition to a magnetically ordered state, the linear positive component in the magnetoresistance of the PrB{sub 6} and NdB{sub 6} compounds becomes dominant, whereas the quadratic contribution to the negative magnetoresistance is completely suppressed in the commensurate magnetic phase of these compounds. The presence of several components in the magnetoresistance has been explained by assuming that, in the antiferromagnetic phases of PrB{sub 6} and NdB{sub 6}, ferromagnetic nanoregions (ferrons) are formed in the 5d band in the vicinity of the rareearth ions. The origin of the quadratic contribution to the negative magnetoresistance is interpreted in terms of the Yosida model, which takes into account scattering of conduction electrons by localized magnetic moments of rare-earth ions. Within the approach used, the local magnetic susceptibility {chi}{sub loc} has been estimated. It has been demonstrated that, in the temperature range T{sub N} < T < 20 K, the behavior of the local magnetic susceptibility {chi}{sub loc} for the compounds under investigation can be described with good accuracy by the Curie-Weiss dependence {chi}{sub loc} {proportional_to} (T - {Theta}{sub p}){sup -1}.

• OSTI ID: 21443665
• Journal Information: Journal of Experimental and Theoretical Physics, Vol. 109, Issue 5; Other Information: DOI: 10.1134/S1063776109110119; Copyright (c) 2009 Pleiades Publishing, Ltd.; ISSN 1063-7761
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ANTIFERROMAGNETISM
ELECTRONS
MAGNETIC FIELDS
MAGNETIC MOMENTS
MAGNETIC SUSCEPTIBILITY
MAGNETIZATION
MAGNETORESISTANCE
MONOCRYSTALS
NEODYMIUM BORIDES
NONLINEAR PROBLEMS
PARAMAGNETISM
PRASEODYMIUM BORIDES
TEMPERATURE DEPENDENCE
BORIDES
BORON COMPOUNDS
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
MAGNETIC PROPERTIES
MAGNETISM
NEODYMIUM COMPOUNDS
PHYSICAL PROPERTIES
PRASEODYMIUM COMPOUNDS
RARE EARTH COMPOUNDS