Critical exponents and intrinsic broadening of the field-induced transition in NiCl${}_2$$\cdot$4SC(NH${}_2$)${}_2$

Abstract

The field-induced ordering transition in the quantum spin system NiCl${}_2$$\cdot$4SC(NH${}_2$)${}_2$ is studied by means of neutron diffraction, AC magnetometry and relaxation calorimetry. The interpretation of the data is strongly influenced by a finite distribution of transition fields in the samples, which was present but disregarded in previous studies. Taking this effect into account, we find that the order-parameter critical exponent is inconsistent with the BEC universality class even at temperatures below 100 mK. All results are discussed in comparison with previous measurements and with recent similar studies of disordered Ni(Cl${}_{1-x}$Br${}_x$)${}_2$$\cdot$4SC(NH${}_2$)${}_2$.

References in corpus (5)

• Bose-Einstein Condensation in Magnetic Insulators
• 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
• Spin Dynamics of $NiC{l}_2-4SC(N{H}_2{)}_2$ in the Field-Induced Ordered Phase
• U(1)-Symmetry breaking and violation of axial symmetry in TlCuCl3 and other insulating spin systems

Cited by in corpus (4)

• Nuclear magnetic resonance study of the magnetic-field-induced ordered phase in the NiCl2-4SC(NH2)2 compound
• Pre-saturation phase in the frustrated ferro-antiferromagnet Pb${}_2$VO(PO${}_4$)${}_2$
• Quantum criticality in a three dimensional spin system at zero field and pressure
• Narrowly avoided spin-nematic phase in BaCdVO(PO${}_4$)${}_2$: NMR evidence