Microscopic evidence for Mn-induced long range magnetic ordering in MAX phase compounds

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• MAX phases are a unique class of layered transition metal carbides and nitrides.
• Understanding the magnetic properties of MAX phases is crucial for their potential applications.
• Doping with manganese (Mn) can significantly alter the magnetic behavior of these materials.

Purpose of the Study:

• To investigate the local microscopic magnetic properties of (Cr$_{1-x}$Mn$_{x}$)$_{2}$AC MAX phases.
• To determine the presence or absence of long-range magnetic order in these doped MAX phases.
• To explore the influence of the 'A' atom (Ge or Ga) on magnetic ordering.

Main Methods:

• Zero and low field nuclear magnetic resonance (NMR) measurements were employed.
• Specific compositions of (Cr$_{1-x}$Mn$_{x}$)$_{2}$GeC and (Cr$_{1-x}$Mn$_{x}$)$_{2}$GaC were synthesized and analyzed.

Main Results:

• Unambiguous evidence for long-range magnetic order was found in (Cr$_{0.96}$Mn$_{0.04}$)$_{2}$GeC.
• Long-range magnetic order was also observed in (Cr$_{0.93}$Mn$_{0.07}$)$_{2}$GaC.
• However, (Cr$_{0.97}$Mn$_{0.03}$)$_{2}$GaC did not exhibit long-range magnetic order under the experimental conditions.

Conclusions:

• The presence of long-range magnetic order in these MAX phases is confirmed for specific compositions.
• A potential dependence of magnetic ordering on the type of 'A' atom (Ge vs. Ga) is indicated.
• These findings contribute to a deeper understanding of magnetism in doped MAX phase materials.