High-field Electron Spin Resonance in Quantum Spin Systems

In this presentation I will review our recent results obtained in low-dimensional and frustrated spin systems using high-field Electron Spin Resonance (ESR) at the National High Magnetic Laboratory, Tallahassee, USA, and the Dresden High Magnetic Field Laboratory, Germany. It includes the observation of the sine-Gordon behaviour of magnetic excitations in quantum spin-chain material Cu-PM, observation of the two-magnon bound states in the new candidate for the magnon Bose-Einstein condensation (BEC) NiCl2-4SC(NH2)2 (known as DTN), antiferromagnetic resonance in the frustrated hexagonal multiferroic material YMnO3, observation of the excitation spectrum in the spin-ladder material BPCB and others. The talk will give also a brief introduction into the recent development of the high-field ESR program at the High Magnetic Field Laboratory in Dresden.