The Structural and Magnetic Properties of CuRh1-x Mn x O2 (0 aparts per thousandcurrency sign x aparts per thousandcurrency sign 0.1) Delafossite Oxide

The CuRh1-x Mn (x) O-2 (0.00 a parts per thousand currency sign x a parts per thousand currency sign 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 (chi) 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-x Mn (x) O-2 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 Delta S (M) of CuRh0.9Mn0.1O2. Using Arrott plots, it was found that the phase transition for this sample at T (N) = 42 K is of second order. The maximum entropy change of similar to 0.017 J/kg K upon a filed variation of similar to 1 T and similar to 0.076 J/kg K upon a filed variation of similar to 5 T was obtained, indicating relatively small magnetic order fluctuations around T (N) .