The Structural and Magnetic Properties of CuRh1−xMnxO2 (0 ≤ x ≤ 0.1) Delafossite Oxide

Abstract

The CuRh1−xMnxO2 (0.00 ≤ x ≤ 0.10) polycrystalline powders were synthesized by the direct solid-state reaction. The magnetic susceptibility was measured in the temperature range of 4–300 K. It was found that the magnetic susceptibility (χ) increases rapidly with the doping of Rh 3+ by Mn 3+ ions with existence of paramagnetic substance at low temperature. For x = 0.1, a development of new antiferromagnetic (AF) transition around 26 K and the magnetic data for CuRh1−xMnxO2 show evidence for weak ferromagnetic (FM) transition between 100 and 130 K. Clear hysteresis loops indicate that FM order exists in Mn-doped samples at 5 K. All samples behave like semiconductors. The ferromagnetism properties can be attributed to the double-exchange interaction between the Mn 3+ and Rh 3+ semiconductor compounds. We analyze the magnetic entropy change ΔSM of CuRh0.9Mn0.1O2. Using Arrott plots, it was found that the phase transition for this sample at TN = 42 K is of second order. The maximum entropy change of ∼ 0.017 J/kg K upon a filed variation of ∼ 1 T and ∼ 0.076 J/kg K upon a filed variation of ∼ 5 T was obtained, indicating relatively small magnetic order fluctuations around TN.