Cracks induced by magnetic ordering in the antiperovskiteZnNMn3

Abstract

${\mathrm{ZnNMn}}_3$ has an unusual cubic-to-cubic structural phase transition near 160 K, which coincides with the onset of the antiferromagnetic (AFM) ordering. The phase transformation involves the formation of microcracks induced by the magnetic moment-dependent lattice expansion, which is also accompanied by an upturn in the resistivity curve $\rho$ $\mathrm{}\left(T\right)\mathrm{}$ near the Néel temperature. With an increasing number of warming and cooling cycles, the $\rho$ $\mathrm{}\left(T\right)\mathrm{}$ curve shifts to progressively higher resistivity values due to the formation of microcracks. The origin of this peculiar behavior is discussed in terms of a reduced mean-free path associated with electron scattering on cracks at constant carrier concentration. In addition, we show that the AFM alignment caused by the interatomic distance-dependent exchange inversion leads to lattice expansion.