Hexagonal Yb1−xLuxMnO3, as a potential candidate for cryogenic magnetic refrigeration (Yb1−xLuxMnO3, x = 0.00–0.30)
摘要
Polycrystalline hexagonal Lu-substituted YbMnO3 compounds, Yb1–xLuxMnO3 (x = 0.00, 0.10, 0.20, and 0.30), were synthesized by the conventional solid-state reaction method, and their magnetocaloric properties were systematically investigated in the cryogenic temperature region. X-ray diffraction confirms the formation of a single-phase hexagonal structure for all compositions. Temperature- and field-dependent magnetization measurements reveal a low-temperature magnetic transition at Tm ≈ 6.5 K, which slightly changed with Lu substitution. The magnetic entropy change (− ΔSM) was evaluated from isothermal magnetization data using Maxwell’s relation. Under an applied magnetic field change of ~ 7 T, the parent YbMnO3 exhibits a maximum entropy change of 6.54 J kg−1 K−1, which gradually decreases to 4.40 J kg−1 K−1 for x = 0.30 due to the progressive replacement of magnetic Yb3+ ions by nonmagnetic Lu3+ ions. Correspondingly, the relative cooling power (RCP) decreases from 78.70 J kg−1 for YbMnO3 to 52.13 J kg−1 for x = 0.30. The effective magnetic moment remains nearly constant (~ 6.4 μB) across the series, indicating that Lu substitution does not significantly alter the intrinsic magnetic behavior. A comparison with reported literature data shows that the present compounds exhibit competitive magnetocaloric performance at low temperatures. The absence of magnetic hysteresis, the appreciable entropy change, and the RCP values highlight hexagonal Yb1−xLuxMnO3 as a promising material for cryogenic magnetic refrigeration applications.