Giant magnetic coercivity in orthorhombic YNi{sub 4}Si-type SmNi{sub 4}Si compound

Magnetic properties, magnetocaloric effect and heat capacity of the YNi{sub 4}Si-type SmNi{sub 4}Si compound have been investigated. SmNi{sub 4}Si exhibits ferromagnetic transition at 17 K. Below ~9 K, the magnetic isotherms of SmNi{sub 4}Si show metamagnetic-like behavior with critical field of 20 kOe at 5 K. Heat capacity measurements of SmNi{sub 4}Si show the electronic heat capacity coefficient γ=94 mJ/(mol K{sup 2}), phonon coefficient β=0.35 mJ/(mol K{sup 4}) and Debye temperature T{sub D}=310 K. The magnetocaloric effect of SmNi{sub 4}Si is calculated in terms of isothermal magnetic entropy change which is obtained by the isothermal magnetization (ΔS{sub m}{sup magn}) and heat capacity measurements (ΔS{sub m}{sup heat}). Both ΔS{sub m}{sup magn} and ΔS{sub m}{sup heat} reach a maximum of –1.0 J/kg K at 17 K for a field change of 50 kOe and they show positive values for a field change of 20 kOe at ~9 K. Below 15 K, SmNi{sub 4}Si shows large magnetic hysteresis with considerable remanence. At 5 K it exhibits giant coercive field of 58 kOe in an applied field of 90 kOe. - Highlights: • YNi{sub 4}Si-type SmNi{sub 4}Si has Curie point at 17 K. • ΔS{sub m}{sup magn} of SmNi{sub 4}Si reaches value of –1.0 J/kg K in 0–50 kOe near Curie point. • ΔS{sub m}{sup magn} of SmNi{sub 4}Si shows value of –0.4 and +0.8 J/kg K at 17 and 9 K in 0–20 kOe. • SmNi{sub 4}Si shows electronic heat capacity the 94 mJ/(mol K{sup 2}) and Debye T{sub D}=310 K. • SmNi{sub 4}Si shows huge magnetic hysteresis with coercive field of 58 kOe at 5 K.