The new High-TC metamagnetic boride Ti2FeOs3B3 containing Fe-ladders: Experimental and computational investigations.

Transition metal-rich borides exhibit a diverse array of crystal structures and intriguing physical properties. Ti 2 FeOs 3 B 3 , an osmium-rich boride featuring B 4 zigzag fragments and iron dumbbell chains (Fe-ladder), was synthesized and investigated for its magnetic properties. Theoretical calculations reveal a strong competition between antiferromagnetic and ferromagnetic states with only around 8 meV per formula unit in favor of the former, thus predicting metamagnetic behavior. Magnetic measurements confirm an AFM transition (T N ≈ 25 K) at a low magnetic field of 0.01 T, but the ferromagnetic state prevails under the influence of stronger magnetic fields leading to a Curie temperature above room temperature (T C ≈ 650 K), suggesting that the weak AFM interchain Fe 2 –Fe 2 interactions at low fields have been completely flipped to FM interactions (θ ≈ 700 K) by the high magnetic field. This work highlights the complex interplay between composition, structure, and magnetic behavior in this compound and opens a new avenue for the discovery of magnetic materials based on the complex Ti 1+ x Rh 2- x + y Ir 3- y B 3 structure type. [Display omitted] • A new metamagnetic transition metal-rich boride Ti 2 FeOs 3 B 3 with Ti 1+ x Rh 2- x + y Ir 3- y B 3 structure type was discovered. • Crystal structure features B 4 zigzag fragments interacting with iron ladders. • DFT calculations reveal a strong competition between antiferromagnetic (AFM) and ferromagnetic (FM) states. • Shows AFM transition (T N ≈ 25 K) at a low magnetic field and FM state (T C ≈ 650 K) at high field. [ABSTRACT FROM AUTHOR]