Investigation of the physical properties of the tetragonal CeMAl4Si2 (M = Rh, Ir, Pt) compounds

TL;DR

This study explores the synthesis, structure, magnetic properties, and electronic behavior of CeMAl4Si2 (M=Rh, Ir, Pt) compounds, revealing diverse magnetic orders and quasi-2D electronic features through experimental and computational methods.

Contribution

It provides new insights into the magnetic ordering and electronic structure of CeMAl4Si2 compounds, combining experimental measurements with electronic structure calculations.

Findings

CeRhAl4Si2 and CeIrAl4Si2 exhibit antiferromagnetic order below 14 and 16 K.

CePtAl4Si2 orders ferromagnetically below 3 K with a magnetic moment of 0.8 μB.

Electronic structure calculations show a quasi-2D Fermi surface.

Abstract

The synthesis, crystal structure, and physical properties studied by means of x-ray diffraction, magnetic, thermal and transport measurements of CeMAl$_{4}$Si$_{2}$ (M = Rh, Ir, Pt) are reported, along with the electronic structure calculations for LaMAl$_{4}$Si$_{2}$ (M = Rh, Ir, Pt). These materials adopt a tetragonal crystal structure (space group P4/mmm) comprised of BaAl$_4$ blocks, separated by MAl$_2$ units, stacked along the $c$-axis. Both CeRhAl$_{4}$Si$_{2}$ and CeIrAl$_{4}$Si$_{2}$ order antiferromagnetically below $T_{N1}$=14 and 16 K, respectively, and undergo a second antiferromagnetic transitition at lower temperature ($T_{N2}$=9 and 14 K, respectively). CePtAl$_{4}$Si$_{2}$ orders ferromagnetically below $T_C$ =3 K with an ordered moment of $\mu_{sat}$=0.8 $\mu_{B}$ for a magnetic field applied perpendicular to the $c$-axis. Electronic structure calculations reveal quasi-2D character of the Fermi surface.