High-field ESR in low-dimensional spin systems

Electron spin resonance (ESR) is traditionally recognized as one of the most sensitive tools for probing magnetic excitations in strongly-correlated spin systems. Among other exchange-coupled spin systems, low-dimensional magnets serve as almost ideal paradigmatic models in quantum magnetism, exhibiting highly unusual ground-state properties and spin dynamics. Here, I review results of our recent high-field ESR studies of some low-dimensional magnets, including quantum spin chains [1], quantum antiferromagnets on triangular lattice [2], Heisenberg spin ladders [3], and quasi-two-dimensional magnets on a honeycomb lattice [4]. In addition, I will give a brief introduction into the high-field ESR facilities at the Dresden High Magnetic Field Laboratory, which allows for multi-frequency ESR experiments in a very broad frequency range (ca 50 GHz - 9 THz) in magnetic fields up to 60 T and above.