Cr3 Triangles induced competing magnetic interactions in the new metal boride TiCrIr2B2: An NMR and DFT study.

The presence of one-dimensional trigonal arrangements of chromium atoms (Cr 3 ) in the structure of TiCrIr 2 B 2 leads to a magnetic transition near ambient temperature. Herein we report an investigation of the nature of electronic and magnetic properties of TiCrIr 2 B 2 via ab initio calculations together with 11 B NMR Knight shift ( K ) and spin-lattice relaxation rate (1/ T 1 ) analysis. The presence of a characteristic rectangular powder pattern below 280 K, absence of a Korringa relation, strong enhancement of 1/ T 1 .T at low temperatures and weak temperature dependence of K indicate competition between antiferromagnetic and ferromagnetic spin fluctuations in the itinerant d -band electrons, in agreement with ab initio calculations. One-dimensional trigonal arrangements of magnetically active elements in intermetallic compounds, as is found in TiCrIr 2 B 2 , are quite rare and could lead to exotic phenomena such as spin-chirality and quantum criticality in low-dimensional frustrated lattices. [ABSTRACT FROM AUTHOR]