Thermodynamic and magnetic analysis of RCo₉Si₄ system with R = Pr, Nd and Sm

Physics department, College of Science, Qassim University, PO 6644, 51452 Buryadh, Kingdom of Saudi Arabia
Institut für Festkörperphysik, TU Wien, 1040 Wien, Austria

Corresponding author: magelhagary@yahoo.com

Received: 29 October 2007
Revised: 11 March 2008
Accepted: 27 March 2008
Published online: 4 June 2008

Abstract

Thermodynamic and magnetic measurements of ternary compounds RCo₉Si₄ with R = Pr, Nd, and Sm were analyzed in order to estimate the magnetic entropy, specific heat jump and effective magnetic moments. The samples show a ferromagnetic behaviour at low temperature with T_C varying from 10 to 35 K. The saturation magnetisation M_s at 2 K with 6 T is found to be about 23.20, 24.94 and 10.70 emu/g for R = Pr, Nd, and Sm, respectively. The total effective magnetic moments μ_eff of RCo₉Si₄ for R = Pr , Nd, and Sm as obtained from the Curie constant C are estimated to be 4.94 μ_B, 5.26 μ_B, and 3.90 μ_B, respectively. The magnetic specific heat jump ΔC_p at T_C is found to be 12, 3.6, and 10.5 J/mol K for RCo₉Si₄ with R = Pr, Nd, and Sm, respectively. Magnetic entropy S_M associated with the magnetic ordering in RCo₉Si₄ (R = Pr, Nd and Sm) were estimated to vary from 19.15 J/mol K and 14.90 J/mol K.