Exploring the synthesis methodology and abnormal thermomagnetic properties of water-quenched alloys with antiperovskite Mn4C phase

We have devised a highly efficient methodology for the synthesis of high-purity Mn4C, 4 C, involving arc-melting, subsequent homogenization, and water-quenching steps. This approach overcomes previous constraints associated with limited batch sizes and low purity, enabling the fabrication of substantially larger quantities. In pursuit of achieving the high-purity Mn4C 4 C phase, we conducted optimization studies on the stoichiometry of Mn/C in the raw materials, as well as on the homogenization temperature and time. Through this optimization process, we successfully produced highly pure Mn4C 4 C ingots by subjecting Mn4.7C 4.7 C alloys to homogenization at temperatures ranging from 1050 to 1200 degree celsius for 5 hours, followed by rapid water quenching. The utilization of water quenching served to stabilize the Mn4C 4 C phase formed at high temperatures during the homogenization process, thus preventing its transformation into undesired low-temperature phases. The magnetic and physical properties of the samples with highly pure Mn4C 4 C phase, quenched from various temperatures, were investigated, revealing subtly distinct characteristics. The pure Mn4C 4 C sample obtained by quenching from 1100 degrees C exhibited a Ne<acute accent>el temperature of approximately 950 K, a saturation magnetization of 8.4 Am2/kg, 2 /kg, and a positive temperature coefficient (alpha) of magnetization of 0.0113 Am2/kg center dot K, 2 /kg center dot K, respectively. Notably, the abnormal augmentation of thermomagnetic properties over a wide temperature range, from 5 to approximately 650 K, underscores the potential of high- purity Mn4C 4 C as a promising candidate for devices where the thermal stability of magnetic properties is of paramount importance.