Co magnetism and related phenomena in the Er(Co 1 − xSi x) 2 compounds

• Published in: Journal of magnetism and magnetic materials 1998-02, Vol.182 (1), p.143-151
• Main Authors: Cuong, T.D., Duc, N.H., Brommer, P.E., Arnold, Z., Kamarád, J., Sechovský, V.
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic conduction in metals and alloys; Electronic transport in condensed matter; Exact sciences and technology; Galvanomagnetic and other magnetotransport effects; Heat capacities of solids; Itinerant electron metamagnetism; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Magnetovolume effects; Metals. Metallurgy; Physics; Rare-earth transition-metal compounds; Resistivity anomalies; Spin-fluctuation scattering; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids
• ISSN: 0304-8853
• DOI: 10.1016/S0304-8853(97)01015-9

Results of magnetic, transport and dilatometric studies of the Er(Co 1− x Si x ) 2 compounds (for x ⩽ 0.15) in ambient and elevated pressures are presented. The Si substitution for Co yields a dramatic increase of T c although the room-temperature lattice volume does not change. The first-order magnetic phase transition at T c observed in ErCo 2 persists for x ⩽ 0.075. The large resistivity drop observed just below T c and the negative magnetoresistance accompanying the field-induced metamagnetic transition above T c are attributed to Fermi surface reconstruction and to quenching of Co 3d spin fluctuations due to Co moment formation. Formation of the Co magnetic moment is reflected also in a pronounced lattice expansion. The resistivity, magnetoresistance and thermal expansion anomalies are progressively reduced with increasing x (and also with external pressure), which can be conceived with a progressively reduced Co moment. Application of external hydrostatic pressure causes reduction of T c at a rate ∂ ln T c/ ∂p ∼ − 30 Mbar −1 in all the studied compounds.