Giant dielectric nonlinearities at a magnetic Bose-Einstein condensation

Abstract

We experimentally investigate the dielectric response of the low-dimensional gapped quantum magnet Cu${}_2$Cl${}_4\cdot$H${}_8$C${}_4$SO${}_2$ near a magnetic field-induced quantum critical point, which separates the quantum-disordered and helimagnetic ground states. The observed magnetocapacitive effect originates from an improper ferroelectric nature of the transition, which itself is perhaps one of the best known realizations of Bose--Einstein condensation of magnons. Despite that, we find that the magnetocapacitive effect associated with the transition exhibits huge and very unusual anharmonicities.

7 pages, 8 figures

References in corpus (12)

• Spin current and magneto-electric effect in non-collinear magnets
• Bose-Einstein Condensation in Magnetic Insulators
• Dual nature of improper ferroelectricity in a magnetoelectric multiferroic
• Direct transition from a disordered to a multiferroic phase on a triangular lattice
• Cupric chloride CuCl2 as an S=1/2 chain multiferroic
• Spin-resonance modes of the spin-gap magnet TlCuCl_3
• A direct measurement of the Bose-Einstein Condensation universality class in NiCl${}_2$-4SC(NH${}_2$)${}_2$ at ultra-low temperatures
• Consequences of spin-orbit coupling for the Bose-Einstein condensation of magnons
• Ferroelectricity from spin supercurrents in LiCuVO4
• U(1)-Symmetry breaking and violation of axial symmetry in TlCuCl3 and other insulating spin systems
• Dimensional crossover in a spin liquid to helimagnet quantum phase transition
• Critical exponents and intrinsic broadening of the field-induced transition in NiCl${}_2$$\cdot$4SC(NH${}_2$)${}_2$

Cited by in corpus (4)

• Multiferroic phases of the frustrated quantum spin-chain compound linarite
• Dielectric relaxation by quantum critical magnons
• Experimental Verification of the Universality of Magnetic-Field-Induced Bose-Einstein Condensation of Magnons
• Critical dielectric susceptibility at a magnetic BEC quantum critical point