Structure, magnetic and electrical transport properties of Mn4-xAgxN compounds

Mn4-xAgxN compounds (x = 0.0, 0.3, 0.6, 1.0) were prepared by milling and subsequently annealing the mixture of Mn2N0.86, Mn, and Ag powders. All compounds display good single-phase characteristics. Both Mn4N and Mn3.7Ag0.3N exhibit ferrimagnetism, and a little Ag replacement of Mn can improve the saturation magnetization. The magnetic transition of Mn3.4Ag0.6N and Mn3AgN below 15 K is from triangular antiferromagnetism to non-coplanar ferrimagnetism, while the ones at 256 and 275 K (Mn3.4Ag0.6N and Mn3AgN, respectively) have been ascribed to the gradual transition, as temperature increases, from the triangular antiferromagnetic structure T5g to a ferrimagnetic-like one. Two minima appear on the p(T) curves for Mn3AgN, with the observation of a positive magnetoresistance throughout the whole tempeature-dependent change.