The B-site sublattice in the double perovskite oxides ABB'O (B: magnetic cation; B': nonmagnetic cation) causes spin frustration, but the relationship between the structure and spin frustration remains unclear although a number of compounds have been studied. The present study systematically investigated AMnB'O ( = 5/2) and found that the frustration factor, defined by = |θ|/ (θ: Weiss temperature; : Néel temperature), scales linearly with the tolerance factor , i.e., octahedral rotation. Unexpectedly, LaMnTaON (space group: 2/) synthesized under high pressure is more frustrated ( = 6) than oxides with similar values, despite the large octahedral rotation due to the small value of 0.914. Structural analysis suggests that the enhanced frustration can be attributed to the site preference of nitride anions at the equatorial positions, which reduces the variance of neighboring Mn-Mn distances. Our findings provide a new guide to control and improve spin frustration in double perovskites with multiple anions.
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http://dx.doi.org/10.1021/acs.inorgchem.1c00927 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China.
The exploration of materials with nanoscale noncollinear configurations has been continuously attracting attention due to the prospective applications in high-performance magnetic devices. Compared to ferromagnetic materials, noncollinear structures in frustrated magnets hold greater research value due to their smaller sizes and unique properties. However, an effective description of the nanoscale noncollinear domain structures in frustrated magnets is lacking.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, United States.
The insulating transition metal nitride CaCrN consists of sheets of triangular [CrN] units with symmetry that are connected via quasi-1D zigzag chains. Due to strong covalency between Cr and N, Cr ions are unusually low-spin, and = 1/2. Magnetic susceptibility measurements reveal dominant quasi-1D spin correlations with very large nearest-neighbor antiferromagnetic exchange = 340 K and yet no sign of magnetic order down to = 0.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry, Clemson University, Clemson, South Carolina 29634-0973, United States.
A new series of 222 adelite-type Co(GeO)(OH) ( = La-Sm) single crystals were grown by a high-temperature, high-pressure hydrothermal method (650 °C and 100 MPa). Single-crystal diffraction refinements yielded chiral one-dimensional (1D) chains of Co along the axis with an average 2.98 Å separation between Co centers in the [CoO(OH)] ribbon chains.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Chemistry, Rice University, Houston, Texas 77005-1892, United States.
Generalized Hartree-Fock (GHF) is a long-established electronic structure method that can lower the energy (compared to spin-restricted variants) by breaking physical wave function symmetries, namely and . After an exposition of GHF theory, we assess the use of GHF trial wave functions in phaseless auxiliary field quantum Monte Carlo (ph-AFQMC-G) calculations of strongly correlated molecular systems including symmetrically stretched hydrogen rings, carbon dioxide, and dioxygen. Imaginary time propagation is able to restore symmetry and yields energies of comparable or better accuracy than CCSD(T) with unrestricted HF and GHF references, and consistently smooth dissociation curves─a remarkable result given the relative scalability of ph-AFQMC-G to larger system sizes.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Université Paris-Saclay, UVSQ, CNRS, GEMaC, 45 Avenue des Etats Unis, 78035 Versailles, France.
Among the large family of spin-crossover (SCO) solids, recent investigations focused on polynuclear SCO materials, whose specific molecular configurations allow the presence of multi-step transitions and elastic frustration. In this contribution, we develop the first elastic modeling of thermal and dynamical properties of trinuclear SCO solids. For that, we study a finite SCO open chain constituted of successive elastically coupled trinuclear (A=B=C) blocks, in which each site (A, B, and C) may occupy two electronic configurations, namely, low-spin (LS) and high-spin (HS) states, accompanied with structural changes.
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