Magnetic and Electrical Properties of a New Series of Rare Earth Silicide Carbides with the CompositionR3Si2C2(R=Y, La–Nd, Sm, Gd–Tm)

Abstract

The 12 title compounds have been prepared by arc-melting cold-pressed pellets of the elemental components and subsequent annealing. They crystallize with an orthorhombic structure and with cell dimensions varying betweena=403.9(1) pm,b=1688.4(2) pm, andc=450.6(1) pm for La3Si2C2anda=379.6(1) pm,b=1532.8(2) pm, andc=414.5(1) pm for Tm3Si2C2. The magnetic properties of these compounds were determined with a SQUID magnetometer between 2 and 300 K with magnetic flux densities up to 5.5 T. Y3Si2C2is a Pauli paramagnet. The cerium atoms in Ce3Si2C2are trivalent; at low temperatures this compound is ferro- or ferrimagnetic with an ordering temperature of 10(±3) K. Pr3Si2C2and Nd3Si2C2are ferromagnetic (TC=25(±3) and 30(±3) K, respectively), whereas the silicide carbidesR3Si2C2withR=Sm and Gd–Tm are antiferromagnetic. Ho3Si2C2, Er3Si2C2, and Tm3Si2C2show metamagnetic transitions. The highest ordering temperature occurs for Gd3Si2C2with a Néel temperatureTN=50(±1) K. The electrical conductivities of several compounds were determined between 5 and 300 K. They indicate metallic behavior, and in several cases they reflect the magnetic ordering temperatures.