Integer spin-chain antiferromagnetism of the 4d oxide CaRuO3 with post-perovskite structure

TL;DR

This paper reports the discovery of integer spin-chain antiferromagnetism in the post-perovskite CaRuO3, revealing localized 4d electron magnetism with a well-characterized antiferromagnetic exchange and anisotropic superexchange bonds.

Contribution

It is the first observation of integer (S=1) spin-chain antiferromagnetism in a 4d electron system, expanding understanding of low-dimensional magnetism.

Findings

Antiferromagnetic spin-chain behavior with -J/kB = 350 K

Localized 4d electron magnetism indicated by small Sommerfeld coefficient

Anisotropic superexchange bonds along the a-axis

Abstract

A quasi-one dimensional magnetism was discovered in the post-perovskite CaRuO3 (Ru4+: 4d4, Cmcm), which is iso-compositional with the perovskite CaRuO3 (Pbnm). An antiferromagnetic spin-chain function with -J/kB = 350 K well reproduces the experimental curve of the magnetic susceptibility vs. temperature, suggesting long-range antiferromagnetic correlations. The anisotropic magnetism is probably owing to the dyz - 2p- dzx and dzx - 2p- dyz superexchange bonds along a-axis. The Sommerfeld coefficient of the specific heat is fairly small, 0.16(2) mJ mol-1 K-2, indicating that the magnetism reflects localized nature of the 4d electrons. As far as we know, this is the first observation of an integer (S = 1) spin-chain antiferromagnetism in the 4d electron system.