Structural, magnetic and electrical transport properties of non-conventionally prepared MAX phases V2AlC and (V/Mn)2AlC

Christin M. Hamm, Michael Dürrschnabel, Leopoldo Molina-Luna, Ruslan Salikhov, Detlef Spoddig, Michael Farle, Ulf Wiedwald, Christina S. Birkel

Materials Chemistry Frontiers, 2018, 2, 483-490, doi: 10.1039/C7QM00488E

Abstract

A plethora of magnetic ground states along with intriguing magnetic properties have been reported in thin films of Mn-containing MAX phases. However, fewer results and therefore less knowledge in the area of bulk magnetic MAX phases exist resulting in many open research questions that still remain unanswered. Synthesis of high quality materials is key and is here achieved for bulk V2AlC and its Mn-doped analogs by means of microwave heating and spark plasma sintering. The obtained materials are carefully characterized by structural and microstructural investigations resulting in an average Mn-content of 2% corresponding to the mean chemical composition of (V0.96±0.02Mn0.04±0.02)2ALC in the Mn-doped V2AlC samples. While the parent MAX phase as well as the sample with the nominally lowest Mn-content are obtained essentially single-phase, samples with higher Mn-levels exhibit Mn-rich side phases. These are most likely responsible for the ferromagnetic behavior of the corresponding bulk materials. Besides, we show Pauli paramagnetism of the parent compound V2AlC and a combination of Pauli and Langevin paramagnetism in (V0.96±0.02Mn0.04±0.02)2AlC. For the latter, a magnetic moment of μM = 0.2(2) μB per M atom can be extracted.

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