Mn-based antiperovskite functional materials: Review of research

Abstract

Our recent research on the Mn-based antiperovskite functional materials AXMn3 (A: metal or semiconducting elements; X: C or N) is outlined. Antiperovskite carbides (e.g., AlCMn3) show large magnetocaloric effect comparable to those of typical magnetic refrigerant materials. Enhanced giant magnetoresistance up to 70% at 50 kOe (1 Oe = 79.5775 Am−1) over a wide temperature span was obtained in Ga1−xZnxCMn3 and GaCMn3−xNix. In Cu0.3Sn0.5NMn3.2, negative thermal expansion (NTE) was achieved in a wide temperature region covering room temperature (α = −6.8 ppm/K, 150 K–400 K). Neutron pair distribution function analysis suggests the Cu/Sn-Mn bond fluctuation is the driving force for the NTE in Cu1−xSnxNMn3. In CuN1−xCxMn3 and CuNMn3−yCoy, the temperature coefficient of resistivity (TCR) decreases monotonically from positive to negative as Co or C content increases. TCR is extremely low when the composition approaches the critical points. For example, TCR is ∼ 1.29 ppm/K between 240 K and 320 K in CuN0.95C0.05Mn3, which is one twentieth of that in the typical low-TCR materials (∼ 25 ppm/K). By studying the critical scaling behavior and X deficiency effect, some clues of localized-electron magnetism have been found against the background of electronic itinerant magnetism.

Prediction of Superconductivity in 3d Transition-Metal Based Antiperovskites via Magnetic Phase Diagram

“…In reality, abundant magnetisms, e.g. antiferromagnetism and non-collinear magnetism, are observed experimentally in the Mn-based antiperovskites 31 . In this sense, our phase diagram can not present the real magnetism of such compounds.…”

A Simple Computational Proxy for Screening Magnetocaloric Compounds

“…Indeed, Gd shows a sizeable magnetic entropy change of 6.1 J kg −1 K −1 and adiabatic temperature change of 6.4 K for an applied field H = 2 T. 16 Phenomenological models can be used to describe the entropy change in these materials, but these models are descriptive rather than predictive. 17,18 The discovery of a "giant" magnetic entropy change in Gd 5 (Si,Ge) 4 in 1997 created new opportunities in the search for magnetocalorics. In Gd 5 (Si,Ge) 4 , a first-order coupled magnetic and structural transition leads to a greatly enhanced ∆S M .…”

“…In Gd 5 (Si,Ge) 4 , a first-order coupled magnetic and structural transition leads to a greatly enhanced ∆S M . [19][20][21] After the discovery of this phenomena, several other systems with known first-order magnetostructural transitions were investigated, yielding some of the most promising magnetocaloric materials, including Fe 2 P-based and La(Fe,Si) 13 -based materials. In these systems, coupling of the spins and the lattice leads to a system with switchable magnetostructural state, so that a moderate magnetic field can induce a large change in the magnetic entropy of the system.…”

A first-principles study on the negative thermal expansion material: Mn3(A0.5B0.5)N (A=Cu, Zn, Ag, or Cd; B=Si, Ge, or Sn)

“…Magnetic antiperovskite nitride Mn 3 (Cu 1-x Ge x )N, 3 a member of the NTE materials, has recently attracted significant attentions, [4][5][6][7][8][9][10][11][12][13][14][15] due to its large isotropic negative thermal expansion over a wide range around the room temperature. Experimentally, the NTE was thought to be caused by the local lattice distortion induced by Ge dopants.…”