Computer predictions on Rh-based double perovskites with unusual electronic and magnetic properties

Abstract

In search for new magnetic materials, we make computer prediction of structural, electronic and magnetic properties of yet-to-be synthesized Rh-based double perovskite compounds, Sr(Ca) 2 BRhO 6 (B=Cr, Mn, Fe). We use combination of evolutionary algorithm, density functional theory, and statistical-mechanical tool for this purpose. We find that the unusual valence of Rh 5+ may be stabilized in these compounds through formation of oxygen ligand hole. Interestingly, while the Cr-Rh and Mn-Rh compounds are predicted to be ferromagnetic half-metals, the Fe-Rh compounds are found to be rare examples of antiferromagnetic and metallic transition-metal oxide with three-dimensional electronic structure. The computed magnetic transition temperatures of the predicted compounds, obtained from finite temperature Monte Carlo study of the first principles-derived model Hamiltonian, are found to be reasonably high. The prediction of favorable growth condition of the compounds, reported in our study, obtained through extensive thermodynamic analysis should be useful for future synthesize of this interesting class of materials with intriguing properties.

Double perovskites with 3d and 4d/5d transition metals: compounds with promises

“…The filling driven FM to AFM, thus is a general feature of hybridization-driven mechanism of magnetization, as has been established in several model calculations [33]. Following, this expectation in recent time metallic antiferromagnetism has been predicted in yet-to-be synthesized Sr 2 FeRhO 6 and Ca 2 FeRhO 6 [34].…”

“…Double perovskite compounds hold promise as starting materials for such exploration, as many of the members in this family show high magnetic transition temperature. Specifically, as discussed above, Sr 2 CrOsO 6 is a ferrimagnetic insulator with T c ∼725 K [34] which is the highest T c magnetic insulator with uncompensated spin moment, known so far. This is remarkable as most known ferromagnetic insulators like EuO, CdCr 2 S 4 , SeCuO 3 are low T c [25][26][27].…”

Structure and magnetism of the Rh4+-containing perovskite oxides La0.5Sr0.5Mn0.5Rh0.5O3and La0.5Sr0.5Fe0.5Rh0.5O3

“…The stabilization of Rh 4+ in the presence of the readily oxidizable Mn 3+ and Fe 3+ cations suggests that the 3d Mn/Fe states and 4d Rh states are of similar energy, so that if the electronic bandwidth of the phases could be increased, by decreasing the magnitude of the octahedral tilting distortion for example, or the 3d and 4d cations could be ordered, correlated electronic behaviour is likely, in line with computational predictions for high-valent rhodium oxides. 41…”

Synthesis, crystal structure, and vibrational studies of the monoclinically distorted double perovskite, Sr2Mn1−xNixTeO6 with (x = 0.25, 0.5, and 0.75)

“…Over the last few decades, the double-perovskite structure compounds with the general formula A 2 BB ’O 6 ( A = alkaline, alkaline-earth, or rare-earth ions, B and B ’ = transition metal ions) have been studied extensively for their potential applications in ferroelectrics, catalysis, magnetic media, and microwave dielectrics (Gandhi and Keshri, 2015; Tasca et al ., 2017; Halder et al ., 2018; Li et al ., 2018). Depending on their valences and relative radii, the B ( B ’) sites can be occupied by two different transition metal ions; therefore, a broad range of chemical and physical properties may be expected in this system (Zamkova et al ., 2013).…”