Enhanced magnetocaloric effect and magnetic phase diagrams of single-crystal GdCrO2

The crystalline structure, magnetism, and magnetocaloric effect of a GdCrO3 single crystal grown with the laser-diode-heated floating-zone technique have been studied. The GdCrO3 single crystal crystallizes into an orthorhombic structure with the space group Prnnb at room temperature. Upon cooling, under a magnetic field of 0.1 T, it undergoes a magnetic phase transition at TN-Cr = 169.28(2) K with Cr3+ ions forming a canted antiferromagnetic (AFM) structure, accompanied by weak ferromagnetism. Subsequently, a spin reorientation takes place at T-SR = 5.18(2) K due to Gd3+-Cr3+ magnetic couplings. Finally, the long-range AFM order of Gd3+ ions establishes at TN-Gd = 2.10(2) K Taking into account the temperature-(in)dependent components of Cr3+ moments, we obtained an ideal model for describing the paramagnetic behavior of Gd3+ ions within 30-140 K. We observed a magnetic reversal (positive -> negative -> positive) at 50 Oe with a minimum centering around 162 K. In the studied temperature range of 1.8-300 K, there exists a strong competition between magnetic susceptibilities of Gd3+ and Cr3+ ions, leading to puzzling magnetic phenomena. We have built the magneticfield-dependent phase diagrams of TN-Gd, T-SR, and TN-Cr, shedding light on the nature of the intriguing magnetism. Moreover, we calculated the magnetic entropy change and obtained a maximum value at 6 K and Delta mu H-0 = 14 T, i.e., similar to Delta S-M approximate to 57.5 J/kg K. Among all RCrO3 (R = 4f(n) rare earths, n = 714) compounds, the single-crystal GdCrO3 compound exhibits the highest magnetic entropy change, as well as an enhanced adiabatic temperature, creating a prominent magnetocaloric effect for potential application in magnetic refrigeration.