Abstract
Recent experiments showed that some perovskite oxyhydrides have surprisingly high magnetic-transition temperature. In order to unveil the origin of this interesting phenomenon, we investigate the magnetism in SrCrO2H and SrVO2H on the basis of first-principles calculations and Monte Carlo simulations. Our work indicates that the Cr-O-Cr superexchange interaction in SrCrO2H is unexpectedly strong. Different from the previous explanation in terms of the H− ion substitution induced increase of the Cr-O-Cr bond angle, we reveal instead that this is mainly because the 3d orbitals in perovskite oxyhydrides becomes more delocalized since H− ions have weaker electronegativity and less electrons than O2− ions. The delocalized 3d orbitals result in stronger Cr-O interactions and enhance the magnetic-transition temperature. This novel mechanism is also applicable to the case of SrVO2H. Furthermore, we predict that SrFeO2H will have unprecedented high Neel temperature because of the extraordinarily strong Fe-H-Fe σ-type interactions. Our work suggests the anion substitution can be used to effectively manipulate the magnetic properties of perovskite compounds.
Highlights
Is, the electron configuration is1(dyz)1(dxz)[1]
To probe the origin of the high TN in SrCrO2H and SrVO2H, we studied the magnetic properties of SrCrO2H, SrVO2H, and LaCrO3 based on the density functional theory (DFT)
We show that due to weaker electronegativity and less electrons of H− ions than those of O2− ions, the substitution of H− ions with O2− ions lead to more delocalized 3d orbitals of Cr3+ ions which make Cr-O-Cr superexchange in SrCrO2H much stronger and leads to a high TN
Summary
Interactions in Perovskite received: September 2015 accepted: November 2015. Recent experiments showed that some perovskite oxyhydrides have surprisingly high magnetictransition temperature. The mechanism that the H− ion induced delocalization of the d orbitals is general and may have profound effect on the electronic and magnetic properties of other perovskite oxyhydrides. Similar to the cases of SrCrO2H and SrVO2H, the weaker electrostatic potential of H− ions exerting on the d electrons of Fe3+ ions leads to more delocalized Fe-d3z2−r2 orbitals, which results in an anomalously strong spin exchange JH. The high magnetic transition temperature in SrCrO2H is revealed to be due to the delocalization of 3d orbitals in perovskite oxyhydrides This is because H− ions have weaker electronegativity and fewer electrons than O2− ions. The delocalization of d orbitals in oxyhydrides discovered in this work is universal and may have profound effects on properties other than the magnetic properties
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
