Ferrimagnetism and spin reorientation in the high-pressure double double perovskites CaMnCrSbO6 and CaMnFeSb

Elena Solana‐Madruga

¹

,

Padraig S. Kearins

²

,

Khalid N. Alharbi

³

et al.

Abstract

Two new CaMnBSbO6 (B = Cr and Fe) high pressure double double perovskites are reported. Spins in CaMnCrSbO6 order below TC = 49 K into a collinear ferrimagnetic arrangement with spins in the xy plane. CaMnFeSbO6 has the same ordered magnetic structure below TC1 = 55 K, but also shows a second magnetic transition at TC2 = 21 K where the spins reorient towards the z axis. This may reflect a greater degree of magnetic disorder for B = Fe and A-B intersite charge transfer may also be significant.

Insights into cation ordering of double perovskite oxides from machine learning and causal relations

“…The distribution of all 410 entries in the dataset are plotted with respect to variations in the tolerance ranges. In Figure 2(b) this distribution is shown for different oxidation states for BB sites, as (2,6), (3,2), (4,2), (4,3) and (4,4), respectively. For AA , the possible oxidation states become (1,3), (3,4), (2,2), (3,2) and (4,4) as represented in Figure 2(c).…”

“…In Figure 2(b) this distribution is shown for different oxidation states for BB sites, as (2,6), (3,2), (4,2), (4,3) and (4,4), respectively. For AA , the possible oxidation states become (1,3), (3,4), (2,2), (3,2) and (4,4) as represented in Figure 2(c). The charge differences (CD) between B and B thus evaluated are 4, 1, 2 and 0, whereas, CD between A and A are 2, 1 and 0, respectively.…”

“…Although construction of reasonably accurate models are possible even using these set of descriptors, it is clear that the utilization DFT-derived features capture the formation of cation ordering better. The classification of C[0], L[0] and R [2] is dependent both on the presence or absence of specific structural modes in the system as well as on their amplitudes. In addition, these functional modes as driven by symmetry also affect cation displacements, cell parameters.…”

“…Cation ordered double perovskites of the form AA BB O 6 with A as an alkaline-earth or rare-earth ion, B and B , as transition metal ions, exhibit a wide range of properties due to their structural and compositional flexibility [1,2]. In particular, a substantial number of compounds within this family of materials as reported by both theoretical and experimental studies, show multiferroic and polar metallic behavior [3][4][5][6][7].…”

CaFeFeNbO6 – an iron-based double double perovskite

“…Many P 4 2 / n AA’BB’O 6 double double perovskites with A’ = Mn have been synthesised at 10 GPa; RMnMnB’O 6 (B’ = Sb 15,16 and Ta 17 ) and CaMnBB’O 6 (B = Mn, Fe, Co, Ni for B’ = Re, 18–20 and B/B’ = Fe/Ta, 21 Cr/Sb, Fe/Sb 22 and Mn/W 23 ); and recently the first non-Mn analogue CaCuFeReO 6 was made at 15.5 GPa. 24 The CaA’FeReO 6 (A’ = Mn, Mn 0.5 Cu 0.5 , Cu) materials are notable as ferrimagnets with Curie temperatures above 500 K and varying magnetoresistance properties.…”