Microwave-Assisted Synthesis of the New Solid-Solution (V<sub>1–<i>x</i></sub>Cr<sub><i>x</i></sub>)<sub>2</sub>GaC (0 ≤ <i>x</i> ≤ 1), a Pauli Paramagnet Almost Matching the Stoner Criterion for <i>x</i> = 0.80
Niels Kubitza, Ruiwen Xie, И. А. Тарасов, Chen Shen, Hongbin Zhang, Ulf Wiedwald, Christina S. Birkel
Abstract
MAX phases that exhibit long-range magnetic order in the bulk are still very hard to synthesize. Chromium and manganese are the cutoff elements when transitioning through the 3dmetals that still form stable full and doped MAX phases, respectively. An iron-based (on the M -site) bulk MAX phase does not exist. Therefore, other strategies to induce long-range magnetic ordering in bulk MAX phases are necessary to open the path to new functional materials. Here, we demonstrate the nonconventional synthesis of a hitherto unknown MAX phase solid-solution (V 1– x Cr x ) 2 GaC by microwave heating. The full series with 0 < x < 1 ( x = 0.20, 0.40, 0.50, 0.60, 0.80) forms almost single phase with minimal differences in their morphology. Their magnetic properties, however, differ rather significantly, with a maximum susceptibility around x = 0.80. Both the experimental and theoretical/ab initio magnetic analysis confirm that the solid-solution (V 1– x Cr x ) 2 GaC is an itinerant Pauli paramagnet that almost fulfills the Stoner criterion for ferromagnetic order (for compositions with x around 0.80). This is a powerful insight into how chemical composition couples with electronic structure and the resulting bulk magnetic properties because it provides crucial guidelines to produce long-range ordered magnetic MAX phases.