Enhanced magnetocaloric effect and magnetic phase diagrams of single-crystal GdCrO${}_3$

Abstract

The crystalline structure, magnetism, and magnetocaloric effect of a GdCrO${}_3$ single crystal grown with the laser-diode-heated floating-zone technique have been studied. The GdCrO${}_3$ single crystal crystallizes into an orthorhombic structure with the space group $Pmnb$ at room temperature. Upon cooling, under a magnetic field of 0.1 T, it undergoes a magnetic phase transition at $T_{\text{N-Cr}}=$ 169.28(2) K with Cr${}^{3+}$ ions forming a canted antiferromagnetic (AFM) structure, accompanied by a weak ferromagnetism. Subsequently, a spin reorientation takes place at $T_{\text{SR}}=$ 5.18(2) K due to Gd${}^{3+}$-Cr${}^{3+}$ magnetic couplings. Finally, the long-range AFM order of Gd${}^{3+}$ ions establishes at $T_{\text{N-Gd}}=$ 2.10(2) K. Taking into account the temperature-(in)dependent components of Cr${}^{3+}$ moments, we obtained an ideal model for describing the paramagnetic behavior of Gd${}^{3+}$ ions within 30--140 K. We observed a magnetic reversal (positive $\to$ negative $\to$ 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 Gd${}^{3+}$ and Cr${}^{3+}$ ions, leading to puzzling magnetic phenomena. We have built the magnetic-field-dependent phase diagrams of $T_{\text{N-Gd}}$, $T_{\text{SR}}$, and $T_{\text{N-Cr}}$, 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 $\Delta {\mu }_{0}H$ = 14 T, i.e., -$\Delta S_{\text{M}}\approx$ 57.5 J/kg K. Among all RCrO${}_3$ (R = $4f^n$ rare earths, $n=$ 7-14) compounds, the single-crystal GdCrO${}_3$ 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.

11 pages, 5 figures

References in corpus (6)

• Field-induced Polar Order at the Néel Temperature of Chromium in Rare-earth Orthochromites: Interplay of Rare-earth and Cr Magnetism
• Giant magnetocaloric effect in magnetically frustrated EuHo${}_2$O${}_4$ and EuDy${}_2$O${}_4$ compounds
• Local inversion symmetry breaking and spin-phonon coupling in perovskite GdCrO3
• Possible magnetic-polaron-switched positive and negative magnetoresistance in the GdSi single crystal
• Crystalline and magnetic structures, magnetization, heat capacity and anisotropic magnetostriction effect in a yttrium-chromium oxide
• Super-Necking Crystal Growth and Structural and Magnetic Properties of SrTb${}_2$O${}_4$ Single Crystals

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