Investigating the magnetic and magnetocaloric behaviors of LiSm(PO 3 ) 4

We report a detailed study on the magnetic behaviors and magnetocaloric (MC) effect of a single crystal of lithium samarium tetraphosphate, LiSm(PO ) . The analyses of temperature-dependent magnetization data have revealed magnetic ordering established with decreasing temperature below , where is the minimum of a d /d curve and varies as a linear function of the applied field . The Curie temperature has been extrapolated from ( ) data, as → 0, to be about 0.51 K. The establishment of magnetic-ordering causes a substantial change in the heat capacity . Above , the crystal exhibits paramagnetic behavior. Using the Curie-Weiss (CW) law and Arrott plots, we have found the crystal to have a CW temperature ≈ -36 K, and short-range magnetic order associated with a coexistence of antiferromagnetic and ferromagnetic interactions ascribed to the couplings of magnetic dipoles and octupoles at the Γ and Γ states. An assessment of the MC effect has shown increases in value of the absolute magnetic-entropy change (|Δ |) and adiabatic-temperature change (Δ ) when lowering the temperature to 2 K, and increasing the magnetic-field magnitude. Around 2 K, the maximum value of |Δ | is about 3.6 J kg K for the field = 50 kOe, and Δ is about 5.8 K for = 20 kOe, with the relative cooling power (RCP) of ∼82.5 J kg . In spite of a low MC effect in comparison to Li(Gd,Tb,Ho)(PO ) , the absence of magnetic hysteresis reflects that LiSm(PO ) is also a candidate for low-temperature MC applications below 25 K.