Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 27: Frustrated Magnets I
MA 27.3: Talk
Wednesday, March 20, 2024, 15:30–15:45, H 2013
Emergent quantum criticality in an Ising spin-1/2 zigzag chain antiferromagnet: CaCoV2O7 — •Arvind Kumar Yogi1, Koushik Chakraborty1, Isha Isha1, A. K. Bera2, and M. Isobe3 — 1UGC-DAE Consortium for Scientific Research, Indore-452001, India — 2Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India — 3Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
We report on a quantum critical behavior in the quasi-1D spin-1/2 zigzag frustrated chain antiferromagnet CaCoV2O7, induced by an applied magnetic field. Below TN = 3.3 K our zero-field neutron diffraction studies reveled the up-up-down-down spin structure, stabilized by an order-by-disorder phenomenon. At base temperature, the magnetic order is suppressed by an applied magnetic field (B), inducing a transition into a quantum paramagnetic state at Bc = 3 T, as revealed by both neutron diffraction and ESR data. The transition exhibits an unusually sharp phase boundary with the critical exponent φ = 0.164(3) ≈ 1/6, in contrast to the earlier experimental observations for uniform spin-1/2 chain systems. Such a sharp QPT is anticipated due to the spin frustration arising from the competing NN and NNN exchange interactions J1 and J2 of the zigzag spin chain.
Keywords: Quantum Magnets; Antiferromagnetism; Magnetism; One-dimensional chains; Frustrated lattice