The enhanced antiferromagnetic interaction and tunable temperature coefficient of resistivity in antiperovskite compounds Mn3−xCoxAgN (0≤x≤0.2)

The magnetic and electric evolution with the substitution level of Co element has been investigated in Mn[Formula: see text]Co x AgN. The DC magnetic measurements demonstrate that the substitution of Co for Mn enhances the antiferromagnetic (AFM) interaction and weakens the magnetic irreversibility at low temperature. The strengthening of AFM order in Mn[Formula: see text]Co x AgN has been attributed to the enhanced Co–Mn AFM interaction and weakened Co–N–Mn ferromagnetic (FM) interaction. Additionally, with the gradual increase of Co content, the temperature coefficient of resistivity (TCR) in paramagnetic (PM) region changes from a positive one to a negative one gradually. When [Formula: see text], the TCR value is only [Formula: see text]5[Formula: see text]ppm/K, which is one magnitude smaller than that of conventional standard resistor materials. The negative TCR phenomenon is closely associated with the Co-element-induced lattice disorder, which leads to the weak localization of conduction electrons.