Composition-Induced Magnetic Transition in GdMn1-xTixSi Intermetallic Compounds for x = 0–1

Abstract

Magnetic intermetallic compounds based on rare earth elements and 3d transition metals are widely investigated due to the functionality of their physical properties and their variety of possible applications. In this work, we investigated the features of the electronic structure and magnetic properties of ternary intermetallic compounds based on gadolinium GdMn1-xTixSi, in the framework of the DFT + U method. Analysis of the densities of electronic states and magnetic moments of ions in Ti-doped GdMnSi showed a significant change in the magnetic properties depending on the contents of Mn and Ti. Together with the magnetic moment, an increase in the density of electronic states at the Fermi energy was found in almost all GdMn1-xTixSi compositions, which may indicate a significant change in the transport properties of intermetallic compounds. Together with the expected Curie temperatures above 300 K, the revealed changes in the magnetic characteristics and electronic structure make the GdMn1-xTixSi intermetallic system promising for use in microelectronic applications.

Antiferromagnetic-to-Ferromagnetic Transition in the GdNiSi1 – xAlx Compound

“…Then it can govern a transition from AFM to FM ordering for the Al-doped compounds, but the presence of Al is also significant for the FM formation, as at x = 0.3, the FM ordering is preserved despite the increase of some Gd-Gd distances. The short Gd-Gd distances were previously found in the other FM Gd-based ternary compounds, for example, in GdRuSi [20]. Also, from Table 1, one can see that in the GdNiSi 0.7 Al 0.3 composition the lattice volume increases by 3.7 % compared to GdNiSi.…”

“…It was recently discovered in GdFe 1−x Ni x Si [19] that for x ≥ 0.3, an AFM ordering becomes energetically preferable rather than FM, as at the lower concentrations of Ni and in pure GdFeSi. Another composition-induced magnetic transition was proposed in GdMn 1−x Ti x Si for x = 0−1 [20]. Recently, the Al-doped GdNiSi 1−x Al x system was first synthesized and experimentally studied in order to improve its magnetocaloric properties, it was found to almost double the values of the relative cooling power for x = 0.2 [21].…”

“…Projected augmented wave dataset for Gd [25] and standard PAW pseudo-potentials of the other elements were chosen from library of Quantum ESPRESSO [26]. Strong electron correlations in the Gd 4f shell were taken into account in the GGA + U approach for the Coulomb parameter as 6.7 eV and Hund parameter as 0.7 eV, the same values as usually used in different Gd non-oxide compounds [1,3,19,20]. Structural data for our calculations were taken from [21], which are close to GdNiSi from [27], for a supercell of GdNiSi with 4 formula units.…”

Theoretical modeling of the electronic structure and Fermi surfaces of Gd4Sb3 and GdSb2 compounds

“…In these PPs, the Gd 4f states are not taken as the valence electronic states. It was demonstrated in [11,20] that a ferromagnetic ordering of the Gd 4f moments provides magnetic moment of about 7 μB/Gd in the Gdbased intermetallic materials.…”