Research Progress on Ni-Based Antiperovskite Compounds

P Tong,Y P Sun

doi:10.1155/2012/903239

Abstract

The superconductivity in antiperovskite compound MgCNi3was discovered in 2001 following the discovery of the superconducting MgB2. In spite of its lower superconducting transition temperature (8 K) than MgB2(39 K), MgCNi3has attracted considerable attention due to its high content of magnetic element Ni and the cubic structure analogous to the perovskite cuprates. After years of extensive investigations both theoretically and experimentally, however, it is still not clear whether the mechanism for superconductivity is conventional or not. The central issue is if and how the ferromagnetic spin fluctuations contribute to the cooper paring. Recently, the experimental results on the single crystals firstly reported in 2007 trend to indicate a conventionals-wave mechanism. Meanwhile many compounds neighboring to MgCNi3were synthesized and the physical properties were investigated, which enriches the physics of the Ni-based antiperovskite compounds and help understand the superconductivity in MgCNi3. In this paper, we summarize the research progress in these two aspects. Moreover, a universal phase diagram of these compounds is presented, which suggests a phonon-mediated mechanism for the superconductivity, as well as a clue for searching new superconductors with the antiperovskite structure. Finally, a few possible scopes for future research are proposed.

Highlights

To explore new superconductors is one of the central issues of material science and condensed matter physics
The researchers have been focusing on two main scopes in this field, namely, the experimental investigations on MgCNi3 single crystals and on the synthesis and physical properties of neighbor compounds of MgCNi3, which have never been included in any review papers
We focus on these two topics, as well as give a phase diagram based on the available data of the lattice constant, the Debye temperature and the density of state at the Fermi level, N(EF), for the Ni-based antiperovskite compounds

Summary

Introduction

To explore new superconductors is one of the central issues of material science and condensed matter physics. J. Cava from the University of Princeton reported the superconductivity in antiperovskite compound MgCNi3 with the transition temperature TC ∼ 8 K (Figure 1) [2]. The researchers have been focusing on two main scopes in this field, namely, the experimental investigations on MgCNi3 single crystals and on the synthesis and physical properties of neighbor compounds of MgCNi3, which have never been included in any review papers. We focus on these two topics, as well as give a phase diagram based on the available data of the lattice constant, the Debye temperature and the density of state at the Fermi level, N(EF), for the Ni-based antiperovskite compounds. The phase diagram supports that the superconductivity observed in the Ni-based. The phase diagram helps explore new superconductors in Ni-based antiperovskite compounds. Some possible future research scopes were proposed in the end of this paper

Experimental Results on Single Crystalline MgCNi3

Research Progress on Ni-Based Antiperovskite Compounds other than MgCNi3

InBNi3

A Universal Phase Diagram

Future Outlook

Conclusion