Band metamagnetism and related phenomena in Er(Co{ital {sub 1{minus}x}}Si{ital {sub x}}){sub 2}
- Department of Metal Physics, Charles University, Ke Karlovu 5, CZ-121 16 Praha 2, (Czech Republic)
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, CZ-162 00 Praha 6, (Czech Republic)
- Physics Department, College of Natural Science, National University of Hanoi, (Vietnam)
We report on magnetic, transport, and cohesive properties of Er(Co{ital {sub 1{minus}x}}Si{ital {sub x}}){sub 2} compounds in varying external conditions ({ital T,H,p}). The localized Er {ital 4f} magnetic moments in ErCo{sub 2} order ferromagnetically below {ital T{sub C}=33} K. The Co {ital 3d} band states form no moment above {ital T{sub C}}, but below {ital T{sub C}} the majority and minority {ital 3d} sub-bands split due to strong {ital 4f{minus}3d} exchange interaction. Consequently, Co moments of {approximately}1 {ital {mu}{sub B}} appear coupled antiparallel to the Er moments. This is accompanied by a {approximately}50{percent} resistivity drop and an abrupt lattice expansion. The sharp magnetization, resistivity, and volume anomalies in the critical temperature region indicate a first order magnetic phase transition. Detailed comparative studies reveal that the onset of Co magnetizm appears at {ital T{sub 0}{approximately}(T{sub C}{minus}1)} K. Si substitution for Co enhances both, {ital T{sub C}} (up to 66 K for {ital x=0.1}) and {ital {Delta}T=T{sub C}{minus}T{sub 0}}, but the lattice parameter remains unchanged. In opposite, both the magnetovolume and resistivity anomaly at {ital T{sub 0}} become reduced. Pressure effect on {ital T{sub C}(T{sub 0})} is large and negative, {partial_derivative}ln{ital T{sub C}/{partial_derivative}p{approximately}{minus}28} Mbar{sup {minus}1} for all {ital x{le}0.1}. Also the resistivity drop at {ital T{sub 0}} and the magnetovolume effect ({ital {omega}{sub s}=3} {ital {Delta}L/L=4.2{times}10{sup {minus}3}} in ErCo{sub 2}) below {ital T{sub 0}} become reduced with increasing pressure. The latter is reflecting reduction of the Co moment gained below {ital T{sub 0}}. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 582037
- Report Number(s):
- CONF-961141--
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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