Frustrated Triangular Magnetic Structures of Mn₃ZnN: Applications in Thermal Expansion

Abstract

One of the specific subjects in frustrated magnetic systems is the phenomenon coupled with noncollinear magnetism, such as zero or negative thermal expansion (ZTE or NTE) in antiperovskite compounds. The first-principles calculations and neutron powder diffraction (NPD) are used to reveal the control of the noncollinear Γ 5g antiferromagnetic (AFM) structure and corresponding thermal expansion properties in Mn 3 Zn 0.875 X 0.125 N (X = Mn, Ge, and Sn). Based on the optimal exchange-correlation functional, our results demonstrate that X (X = Mn, Ge, and Sn) doping at Zn site could stabilize the noncollinear Γ 5g AFM structure and produce magnetovolume effect (MVE). The predictions of Γ 5g AFM ground state and MVE is further verified by the NPD results of Mn 3 Zn 0.83 Mn 0.15 N 0.99 . Intriguingly, this special magnetic structure with strong spin-lattice coupling can be tunable to achieve ZTE behavior. On the basis of these results we suggest that frustrated magnetic systems with noncollinear Γ 5g AFM structure of Mn atoms in Mn 3 ZnN series of compounds are favorable candidates for a new class of ZTE material.

Multifunctional Antiperovskites driven by Strong Magnetostructural Coupling

“…3(a)). 11,12,61 The average of the evaluated ∆a/a 0 is in good agreement with the experimental observation except for Mn 3 GaN (see Fig. 3(a)).…”

“…NTE materials exhibit contraction in the lattice parameters with respect to temperature in contrast to most materials. 61 To study NTE of APVs, we evaluated the relative change in the lattice constants ∆a/a 0 on the transition from the noncollinear magnetic ground state to PM state (where a 0 is the lattice constant of Γ 4g or Γ 5g noncollinear state and ∆a is lattice constant difference between PM and Γ 4g or Γ 5g state) and compared with the ∆a/a 0 values obtained from the experimental measurement at their transition temperature (see Fig. 3(a)).…”

Effects of Cr Substitution on Negative Thermal Expansion and Magnetic Properties of Antiperovskite Ga1−xCrxN0.83Mn3 Compounds

“…From then on, many studies reported the NTE properties in ANMn 3 (A = Zn, Ga, Ag, and Cu) by substituting A with non-magnetic elements, such as Ge, Sn, Si (Sun et al, 2007, 2010a,b; Huang et al, 2008; Takenaka et al, 2008; Dai et al, 2014). Neutron diffraction studies indicated that the pronounced MVE occurs due to the ordering of the non-collinear triangular Γ 5g AFM spin configuration, and the non-magnetic element doping slows down the ordering of Γ 5g AFM phase (Iikubo et al, 2008a; Song et al, 2011; Deng et al, 2015a,b). Local structure measured via the neutron pair distribution function (PDF) (Iikubo et al, 2008b; Tong et al, 2013a) and x-ray absorption fine structure measurements (Matsuno et al, 2009) suggested a strong relation between the broadening of AFM transition and the local lattice distortions, though a detailed mechanism is still under debate (Tong et al, 2013a).…”

Unusual Electrical Transport Driven by the Competition between Antiferromagnetism and Ferromagnetism in Antiperovskite Mn3Zn1−xCoxN

“…Among these antiperovskite compounds, Mn 3 ZnN with the so-called noncollinear Γ 5g antiferromagnetic (AFM) structure, has attracted considerable attention [15,16]. Previous reports have demonstrated that Mn 3 ZnN undergoes an AFM transition at around 180 K, responsible for a resistive-switching phenomenon [17], and two cubic phases appear in a given temperature range [18].…”